Close Menu X

Genesis 21:1-34: The Faithfulness of God

March 26, 2023 Speaker: Josh Tancordo Series: Genesis: In the Beginning

Topic: Default Passage: Genesis 21:1–34

Genesis 21:1-34: The Faithfulness of God

We’ve been working our way passage by passage through the book of Genesis, and today the next passage we come to is Genesis 21:1-34 so I’ll be reading a selection of verses from that passage. It says,

1 The Lord visited Sarah as he had said, and the Lord did to Sarah as he had promised. 2 And Sarah conceived and bore Abraham a son in his old age at the time of which God had spoken to him. 3 Abraham called the name of his son who was born to him, whom Sarah bore him, Isaac. 4 And Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. 5 Abraham was a hundred years old when his son Isaac was born to him. 6 And Sarah said, “God has made laughter for me; everyone who hears will laugh over me.” 7 And she said, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.” 8 And the child grew and was weaned. And Abraham made a great feast on the day that Isaac was weaned. 9 But Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, laughing. 10 So she said to Abraham, “Cast out this slave woman with her son, for the son of this slave woman shall not be heir with my son Isaac.” 11 And the thing was very displeasing to Abraham on account of his son. 12 But God said to Abraham, “Be not displeased because of the boy and because of your slave woman. Whatever Sarah says to you, do as she tells you, for through Isaac shall your offspring be named. 13 And I will make a nation of the son of the slave woman also, because he is your offspring.” 14 So Abraham rose early in the morning and took bread and a skin of water and gave it to Hagar, putting it on her shoulder, along with the child, and sent her away. And she departed and wandered in the wilderness of Beersheba. 15 When the water in the skin was gone, she put the child under one of the bushes. 16 Then she went and sat down opposite him a good way off, about the distance of a bowshot, for she said, “Let me not look on the death of the child.” And as she sat opposite him, she lifted up her voice and wept. 17 And God heard the voice of the boy, and the angel of God called to Hagar from heaven and said to her, “What troubles you, Hagar? Fear not, for God has heard the voice of the boy where he is. 18 Up! Lift up the boy, and hold him fast with your hand, for I will make him into a great nation.” 19 Then God opened her eyes, and she saw a well of water. And she went and filled the skin with water and gave the boy a drink. 20 And God was with the boy, and he grew up. He lived in the wilderness and became an expert with the bow. 21 He lived in the wilderness of Paran, and his mother took a wife for him from the land of Egypt.

May God bless the reading of his Word.

Let’s pray: Father, every word we find written in this passage is a priceless treasure because it’s your self-revelation. Thank you that we don’t have to guess about who you are or how we can know you or live in the realm of your blessing. You’ve already told us in your Word. So help us to understand everything we need to understand and be changed in every way we need to be changed through the power of the Holy Spirit. It’s in Jesus’ name we pray, amen. It probably won’t surprise you to learn that most Americans today have less confidence in public institutions than they’ve had in previous years. In fact, the average level of confidence in most institutions is actually at historic lows. The most recent data is from 2022 and comes from Gallup. When people were asked how much confidence they have in various institutions, only 23% said they had a “great deal” or “quite a lot” of confidence in the presidency—23%. Only 25% said they had a “great deal” or “quite a lot” of confidence in the Supreme Court. And only 7% said they had one of those two levels of confidence in Congress. That was the lowest-ranking institution in the entire survey. The police came in at 45%, the criminal justice system came in at 14%, and public schools came in at 28%. The same percentage of people, 28%, indicated confidence in organized labor, 14% indicated confidence in big business, and 38% indicated confidence in the medical system. As for the media, only 16% of people had either a “great deal” or “quite a lot” of confidence in news from the internet. Newspapers also came in at 16%. And television news was only at 11%. 

And, for most of these institutions, these numbers represent record-breaking lows. For all but three of the institutions, there was a lower level of confidence in 2022 than in any other year previously since they began keeping track of these things in the 1970’s. So, basically, trust in just about everything is at an all-time low. And the sad thing is that, for most of us, these statistics probably aren’t even very surprising. Many of us probably also believe that there’s good reason for the widespread lack of trust in a lot of these institutions. We live in a time when a lot of people in a lot of different institutions have shown themselves to be untrustworthy. 

Yet, that just makes me appreciate what we know to be true about God even more. Those of us who are Christians understand that we serve a God whom we can trust completely—a God who never lies, who never breaks his promises, who never misrepresents his intentions or distorts the facts, and who always acts and speaks with absolute integrity. That means if God does something, we know it’s right, and if he says something, we know it’s true. And that’s what we see confirmed here in our main passage of Genesis 21. 

The main idea of this passage is that God shows himself faithful in fulfilling his promise and accomplishing his purpose. Again, God shows himself faithful in fulfilling his promise and accomplishing his purpose. So, let’s take a closer look at both of these realities as we see them illustrated in this passage. First, we’ll see how God’s faithful in fulfilling his promise and second how he’s faithful in accomplishing his purpose. 

God Is Faithful in Fulfilling His Promise

Ever since Genesis 12, we’ve seen God promising Abraham repeatedly that he would have a son. We find these promises in Genesis 12:2, Genesis 13:15, Genesis 15:4, Genesis 17:4, Genesis 17:16, and Genesis 18:10. All of these verses record specific promises from God that, even in his old age, Abraham would have a son. And even the passages in these chapters that don’t specifically mention the son God would give Abraham are still written with that promise in view. Just about every passage either heightens our anticipation of the fulfillment of God’s promise or presents an obstacle or threat to his promise being fulfilled. So, in various ways, this promised child is what the entire narrative has been focusing on and looking forward to ever since Genesis 12. The suspense has been gradually building. 

And now, finally, after Abraham and Sarah have been waiting for 25 years for God to fulfill his promise, here’s what we read in Genesis 21:1-2: 1 The Lord visited Sarah as he had said, and the Lord did to Sarah as he had promised. 2 And Sarah conceived and bore Abraham a son in his old age at the time of which God had spoken to him. So, God was faithful to fulfill his promise. This is emphasized three times in these two verses. In verse 1, we read that “The Lord visited Sarah as he had said” and “did to Sarah as he had promised.” Then verse 2 states that Sarah bore Abraham a son “at the time of which God had spoken to him.” So, just in case anyone might have somehow missed it, these verses make very clear that Isaac’s birth was no ordinary birth but was rather the fulfillment of God’s promise to Abraham. 

The passage then continues in verses 3-6: 3 Abraham called the name of his son who was born to him, whom Sarah bore him, Isaac. 4 And Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. 5 Abraham was a hundred years old when his son Isaac was born to him. 6 And Sarah said, “God has made laughter for me; everyone who hears will laugh over me.”

Now, this isn’t the first time laughter has come up. In Genesis 17:17, Abraham laughed what appears to have been, judging from the context, a laugh of joyful anticipation. Then, in Genesis 18:12, Sarah laughed a laugh of doubt or skepticism—much like the kind of laughter that might result from me saying I was certain the Pittsburgh Pirates would win the World Series this year. Probably not going to happen, right? So, those are two very different kinds of laughter—a laughter of joyful anticipation and a laughter of skepticism. Yet, they both seem to come together here in verse 3 of our main passage in the name of this promised child. He’s given the name “Isaac,” which means “he laughs.” Sarah then says in verse 6, “God has made laughter for me; everyone who hears will laugh over me.” And that, presumably, would be a laughter of rejoicing, in which both Sarah and everyone hears about what God’s done rejoices in God’s goodness toward her and the way God’s shown himself faithful to the promise he made. It may have taken a long time, but God was faithful to his promise. 

And, friends, the same is true for us today. God’s given us some incredible promises in the Bible, and he won’t fail to fulfill a single one. Even though we might find it necessary to take promises that various other people make to us with a grain of salt, we can have absolute certainty that God will keep every promise to us he’s ever made. 

Let me just give you a few of what I find to be the most meaningful of these promises—because, I don’t know about you, but there are times in my life when God’s promises have been my lifeline. When I’ve felt myself sinking in the tumultuous waters of difficult seasons in my life, the promises of God we find in Scripture have been the floatation devices that have held me up and sustained me through those seasons. I don’t think there’s anything else that even comes close to providing the kind of comfort we find in God’s promises.  

So here are just a few of those promises. For starters, there’s one we recite every week at the conclusion of our Worship Gathering. In Matthew 28:20, Jesus assures us, “And behold, I am with you always, to the end of the age.” The God of the universe promises to be present with us, walking with us every step of the way, through all of the storms and trials we face in life. We’ll never be alone. Similarly, we read in Romans 8:38-39 that nothing can separate us from God’s love. Paul writes, 38 For I am sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, 39 nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord. 

In addition, just a few verses before that, we learn that God works in and through all things for the good of his people. 

Romans 8:28 tells us, “And we know that for those who love God all things work together for good, for those who are called according to his purpose.” Not one drop of suffering will ever be wasted. We also find numerous promises about God answering our prayers. Just to state one of them, Jesus promises in John 15:7 that “If you abide in me, and my words abide in you, ask whatever you wish, and it will be done for you.”

There are also promises related to our struggles with sin. For example, we’re told in 1 Corinthians 10:13 that “No temptation has overtaken you that is not common to man. God is faithful, and he will not let you be tempted beyond your ability, but with the temptation he will also provide the way of escape, that you may be able to endure it.” And for those times when we wonder whether we’ll ever be able to overcome a certain sinful tendency with which we’ve been struggling for a long time, we find this guarantee in Philippians 1:6, which we actually looked at last week. Paul says, “And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ.” No matter how often we stumble or how hard we fall, the same God who began a good work in us at our conversion will faithfully bring that good work to completion until the day Jesus comes back. 

God also promises to comfort us no matter what we face in our lives. As we read in 2 Corinthians 1:3-4, 3 Blessed be the God and Father of our Lord Jesus Christ, the Father of mercies and God of all comfort, 4 who comforts us in all our affliction…. We may also find ourselves at times facing financial uncertainty and be tempted to wonder whether we’ll have enough money to pay the bills. Yet, there’s a promise for that as well. Speaking of material necessities, Jesus tells us in Matthew 6:33, “But seek first the kingdom of God and his righteousness, and all these things will be added to you.” 

We may also find ourselves weighed down, from time to time, with all sorts of other burdens and anxieties. Yet Jesus says in Matthew 11:28-29, 28 Come to me, all who labor and are heavy laden, and I will give you rest. 29 Take my yoke upon you, and learn from me, for I am gentle and lowly in heart, and you will find rest for your souls. Similarly, we’re also promised that God will replace our anxiety with his perfect peace when we pray. In Philippians 4:6-7, Paul writes, 6 [D]o not be anxious about anything, but in everything by prayer and supplication with thanksgiving let your requests be made known to God. 7 And the peace of God, which surpasses all understanding, will guard your hearts and your minds in Christ Jesus. 

And, brothers and sisters, these are just some of the promises related to our present lives here on earth. We haven’t even gotten to the promises related to eternity yet. One promise related to eternity is one that might not initially seem very comforting, but, if you’ve ever been the victim of a significant act of evil, then you know how helpful this promise can be—the promise that God will judge the wicked. Romans 12:19 states, “Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, “Vengeance is mine, I will repay, says the Lord.” Yet, thankfully, for those of us who put our trust in Jesus, we’re promised that we won’t ever have to face that judgment. To quote another verse we looked at last week, 1 John 1:9 assures us that “If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.” Along those same lines, believers are also promised eternal life in the very presence of God. As John 3:16 so famously says, “For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.”

Among countless other blessings, this eternal life will involve an end to all our suffering. Speaking of the heavenly existence of God’s people, Revelation 21:4 promises that “[God] will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain anymore, for the former things have passed away.” We’re even promised rewards in heaven that correlate to how faithfully we’ve engaged in ministry for the Lord while on earth. In 1 Corinthians 3:8, Paul writes that “each will receive his wages according to his labor.”

And let me tell you: all of this is just the tip of the iceberg of the precious promises we find in the pages of Scripture. Perhaps it might be a good idea for us to familiarize ourselves with these promises so they can be the comfort God’s designed them to be. As the Psalmist writes in Psalm 119:50, “This is my comfort in my affliction, that your promise gives me life.” God’s promises are the source of immeasurable comfort—but only if we familiarize ourselves with them and study them and hide them in our hearts. You know, in order to benefit from water, you have to drink it. In order to benefit from medicine, you have to take it. And in order to be comforted and sustained and upheld by God’s promises, we have to be thoroughly familiar with them so that the Holy Spirit can bring them to our minds at the appropriate times. Because, I don’t know about you, but for me, the Holy Spirit hasn’t ever brought a verse to my mind that I didn’t first read and learn and seek to internalize. That’s just the way he works. The Holy Spirit doesn’t operate in a mental vacuum.

Now, making our way back to our main passage of Genesis 21 after that brief excursion, there’s another way in which God keeping his promise to Abraham is relevant for us today. As we observe God’s faithfulness to his promise in bringing about Isaac’s birth, we’re reminded that God always speaks truthfully. Even though it seemed impossible from a human perspective, since Sarah was well past the age of childbearing, Isaac’s birth nevertheless happened just as God said it would—and even at the time when God said it would happen. So, here in Genesis 21, God’s words are shown to be true without any mixture of error or falsehood. 

And that’s the case not only here in this instance but in every instance. We’re told very clearly in Numbers 23:19, “God is not man, that he should lie, or a son of man, that he should change his mind. Has he said, and will he not do it? Or has he spoken, and will he not fulfill it?” We’re also told in Proverbs 30:5 that “Every word of God proves true” and in Titus 1:2 that he’s a God “who never lies” and in Hebrews 6:18 that “it is impossible for God to lie.”

And because God always speaks truth without any mixture of falsehood, we also are called to speak in the same manner. Ephesians 5:25 commands us, “Therefore, having put away falsehood, let each one of you speak the truth with his neighbor….” And I believe this is especially important for us to keep in mind given the fact that our society, in general, seems to be less and less concerned about truth-telling and more and more tolerant of falsehood and deception. It’s just accepted that people are going to lie and that, in most cases, that’s kind of okay. But, as Christians, we’re called to rise about that. As those who serve a God who always speaks what’s true, we should likewise be absolutely committed to speaking truth and maintaining the highest standards of personal integrity. 

So, very briefly, here are ten ways in which we can sometimes fall short of telling the truth. By the way, if you’re taking notes, I apologize if you’re running out of space on your bulletin. I know I just gave you one lengthy list, but here’s another. Good luck trying to find a place to write it down. 

But one way we can fall short of telling the truth is the classic bold-faced lie, in which we say something that’s just blatantly untrue and often known by others to be untrue. Another kind of lie is a fabrication, in which we invent supposed “facts” that we want to be true out of thin air and try to pass them off as the truth. Then, third, there’s also exaggeration, which is based on the truth but that gives the truth a little boost to make it sound more impressive or, in some cases, more extreme. And the flip side of that is minimization, in which we deliberately downplay something, such as our role or responsibility in a situation that turned out poorly. 

Fifth, it’s possible to lie through misrepresentation, in which we distort another person’s statement or argument in order to make a point we want to make. And, sixth, there’s also plagiarism, in which we try to pass off someone else’s work as if it were our own. 

Seventh, we can lie through a broken promise, in which we fail to follow through on commitments we’ve made. Then an eighth way of lying is by telling what we might call lies of omission, in which we conveniently fail to mention certain facts that are important for correctly understanding a certain situation. Ninth is hypocrisy, in which we portray ourselves as being somehow different than who we really are. And for everything else, let me suggest the broadest category of deception, which is sort of a catch-all category that covers every way in which we might deliberately try to mislead others. Even if we don’t say anything that’s technically untrue, it’s still possible to speak in such a way that deliberately gives people the wrong idea about something. 

So, again, those are ten ways in which we can fall short of the standards of truth-telling to which God calls us. Although we might be in a society that’s swimming in its own lies and in which lying is, to a large degree, both expected and accepted, we, as Christians, serve a God of truth and are therefore instructed to be truth-tellers ourselves. 

God Is Faithful in Accomplishing His Purpose

Now, all of that’s related to the faithfulness God demonstrates in keeping his promise to Abraham by miraculously bringing about Isaac’s birth. God shows himself faithful in fulfilling his promise. However, as we continue moving through Genesis 21, we encounter a similar but distinct aspect of God’s faithfulness. We see that God’s faithful not only in fulfilling his promise but also in accomplishing his purpose. It’s God’s devotion to his purpose that leads him to do what he does in the subsequent verses. 

Look at verses 8-13: 8 And the child grew and was weaned. And Abraham made a great feast on the day that Isaac was weaned. 9 But Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, laughing. 10 So she said to Abraham, “Cast out this slave woman with her son, for the son of this slave woman shall not be heir with my son Isaac.” 11 And the thing was very displeasing to Abraham on account of his son. 12 But God said to Abraham, “Be not displeased because of the boy and because of your slave woman. Whatever Sarah says to you, do as she tells you, for through Isaac shall your offspring be named. 13 And I will make a nation of the son of the slave woman also, because he is your offspring.” 

So, here we see a situation that came about because Abraham and Sarah had previously tried to take things into their own hands and give God a little help in keeping his promise. After several years, Abraham and Sarah had become tired of waiting for the child God had promised them and had decided it would be a good idea for Abraham to sleep with one of Sarah’s maidservants named Hagar and try to have a son that way. And sure enough, Abraham got Hagar pregnant, and that child was named Ishmael. 

But that was a sinful deviation from God’s plan. And, in these verses, we can see what a big mess it made. The text says that Sarah saw Hagar’s son Ishmael “laughing” at her own son Isaac. By the way, there’s that theme of laughing again. I don’t know if there were deposits of happy gas in that area or what it was, but everybody seems to be laughing in these chapters. Yet, the word translated “laughing” in this verse actually seems to carry the sense of “mocking.” In Galatians 4:29, the Apostle Paul even writes that Ishmael was “persecuting” Isaac. So this wasn’t some sort of innocent laughter but rather a laughter of contempt. 

And the ultimate result of this incident, which ends up being confirmed by God, is that Hagar and Ishmael have to go. It’s clear that this is more than just your typical case of sibling rivalry and that Ishmael represents a direct threat to what God intends to accomplish through Isaac. So, it’s necessary for Ishmael and his mom Hagar to leave. From the very beginning, God had chosen Isaac to be the one through whom God’s covenant with Abraham would be fulfilled and through whom blessing would one day flow to the entire world, and God wasn’t going to let anything stand in the way of that purpose being accomplished. Again, he was faithful in accomplishing his purpose. 

And there’s no question that bidding farewell to Ishmael was incredibly painful for Abraham. But, again, it was something he had brought on himself through his sinful deviation from God’s will. Fortunately, God promises to bless Ishmael also and make him into a great nation, though separately from Isaac. We also read in verses 14-21 how God graciously watches over Hagar and Ishmael after they leave. It reminds me of Psalm 34:18, which says that, “The Lord is near to the brokenhearted and saves the crushed in spirit.” But that doesn’t change the fact that God was determined to accomplish his purpose through Isaac. There’s a great constancy we see in God that we should be thankful for. Although people might sometimes purpose something but then lose interest or change their minds or not follow through for whatever reason, God’s always faithful to accomplish his purposes—just as he shows himself to be here in Genesis 21 with Isaac. 

And that’s also a great reminder that, even though we might sometimes make some very foolish decisions, as Abraham did, that often bring tremendous sorrow and heartache, we can never ultimately derail God’s plans for us. Just to give a few examples, maybe you’ve unexpectedly become pregnant or gotten someone pregnant outside of marriage. Or maybe, as a Christian, you’ve married someone who’s not a Christian and thereby, as Scripture says, become “unequally yoked.” Or maybe you’ve engaged in some sort of criminal activity that’s led to legal consequences. Or maybe you’ve lived a lifestyle that’s resulted in an STD. Or maybe you’ve had an abortion that haunts you to this day. Regardless of what you’ve done or what messes you’ve made, God can take the tangled threads of your life that, humanly speaking, seem impossible to straighten out and weave them into a beautiful tapestry.

I even think of the people whose stories I read online who have gone through so-called “gender-affirming surgeries” that they now realize were a huge mistake and are causing all kinds of medical issues for them. And, to be honest, I think we’re going to see more and more of these horror stories all over the place. I think society’s about to be inundated with them. Yet, even in those kinds of extreme situations, God can take the tangled messes people have made of their lives and work in the most beautiful ways. Just as we see with Abraham, God can overcome it all to accomplish his good purposes. Again, we might have to endure some painful consequences, just as Abraham had to endure, but we can’t derail the good plans God has for us in and through Jesus Christ. God offers us a grace, through Jesus, that transcends anything we may have done in the past. But the important thing is that we recognize that grace does indeed come through Jesus. 


You see, Isaac may be the immediate focus of these chapters of Genesis, but he’s not the ultimate focus. As we see in Galatians 3:16, the true and ultimate “offspring” of Abraham wasn’t Isaac but rather Jesus. The role of Isaac is simply to foreshadow Jesus. Jesus is the quintessential offspring of Abraham. Like Isaac, God’s people had to wait a long time for Jesus to be born. In fact, they had to wait centuries. But God fulfilled his promise, just as he always does, when he miraculously enabled not Sarah this time but rather Mary to conceive and give birth to the one who would become the Savior of the world. God had promised Abraham way back in Genesis 12:3 that, through him, all the nations of the earth would be blessed. And that blessing came ultimately through Jesus. 

And the way Jesus accomplished that was by dying in our place. Even though our sins deserve God’s judgment, Jesus endured that judgment in our place on the cross. His death atoned for our sin so that, instead of facing the justice we deserve, we can receive the grace we don’t deserve. Jesus then resurrected from the dead and now stands ready to rescue everyone who will put their trust in him. Jesus can rescue you from whatever sins you’ve committed and whatever messes you’ve made. Psalm 103 speaks of him as the one “who forgives all your iniquity, who heals all your diseases, [and] who redeems your life from the pit.” He can do that for you if you’ll stop trusting in yourself and your own efforts to get right with God and instead put your trust in him. As we’ve seen in Genesis 21, God’s faithful to fulfill his promises and accomplish his purposes, but both those promises and those purposes find their ultimate fulfillment in and through Jesus Christ.