So That No One May Boast - Genesis 21:1–21

Have you ever had a problem that you wanted desperately to fix, but you couldn’t?

One of my hobbies is playing the guitar, and many years ago, I purchased what was and still is the most valuable acoustic guitar I’ve ever had. Then one night, the unthinkable happened. I was coming down the stairs of our home at that time (this was about 12 years ago). At the bottom of our stairs was a flat wood surface. I was wearing socks, no shoes, carrying the guitar by the neck; and when I stepped onto the wood surface, I slipped.

As I fell, the base of the guitar slammed into the hard corner of a stair, and the damage to the guitar was very bad. I was in total shock; my wife cried. There was no chance I could fix it. In fact, I didn’t know if anyone could. I sent a picture to a friend who had a lot of guitar knowledge, and he gave me no hope.

You know, for all the problems that are within our ability to fix, there are many that are not. Sometimes we have to call on the help of someone who is able, and sometimes, there is no one who is able to fix the problem.

The Scriptures of the OT and NT tell us that we all have a problem that we cannot fix. It’s our greatest problem, much bigger than any of the problems we face each day, much bigger than the many problems in this nation or throughout the world. The problem is how to be made right with God or be accepted by Him and have peace with Him when He is entirely holy and we are sinners.

And not only does the problem exist, but we naturally think we can do something to fix it, which only makes it worse. We appeal to who we are and how we’ve lived. But the Scriptures are clear that human effort cannot fix the problem. It can’t even touch it.

And yet, long ago God promised to fix it. God promised redemption. He can and He has dealt with the problem. God promised to make peace. And our only hope is in His redemptive promise. It is a promise fulfilled slowly over time, leading up to the person and work of the Lord Jesus Christ.

Jesus came into the world to represent sinners through His life, death, and resurrection, so that “in Him,” as the Scriptures say, sinners could have peace with God. And this is only by what the Bible calls “grace.” It is undeserved favor. This is why the apostle Paul told the churches, “By grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast.”

No one may boast of earning salvation from sin and death by their own means, and no one may boast of keeping salvation by their own strength.

No one may boast of gaining God’s favor by their own volition or remaining in God’s favor by their own power.

No one may boast of having done anything to solve their sin problem by their own ability.

Instead, we should say along with the Paul, “Far be it from me to boast except in the cross of our Lord Jesus Christ.” The cross of Jesus Christ is representative of His whole saving work.

But when it comes to the fulfillment of God’s redemptive promise, should the cross of Jesus and all it represents really be our only boast? What about what we do?

What God can do and what humans can do are compared in this chapter. They’ve compared over and over in Genesis, but here, very clearly. And we see three things in this chapter concerning the role of human effort in the fulfillment of God’s redemptive promise.

Notice the outline on pages 6 and 7 in your WG. As God fulfills His redemptive promise, human effort makes no contribution (vv.1-7), it secures no inheritance (vv.8-14), and it delivers only death (vv.15-21). No one can boast of having done anything to fix their greatest problem. Now let’s look closer at this passage.

It begins with the long-awaited birth of Isaac, the promised child. Abraham and Sarah had waited for at least 25 years. During that time, they believed God, but they also grew impatient and took matters into their own hands.

They could not conceive, and at one point, Sarah encouraged Abraham to have a child with their servant Hagar, which produced the boy Ishmael. But God confirmed that he was not the child of the promise. Walking by faith was a struggle at times; they demonstrated that they were sinners in need of God’s grace.

But God is faithful, and notice the second half of verse 1, “the LORD did to Sarah as he had promised.” Though she was elderly and barren, God caused her to conceive a child, just as He said He would. Abraham names the boy “Isaac” according to God’s command, and Moses is certain to add at the end of verse 3, “whom Sarah bore him.” Just in case you missed that!

Abraham was 100 years old at that point. But notice the focus on Sarah in verses 6 and 7. She said, “God has made laughter for me.” When she first heard the promise of God, she laughed in disbelief. Isaac’s name in Hebrew means, “he laughs.” God has made Sarah laugh with joy.

But interestingly, she adds in verse 6, “everyone who hears will laugh over me.” This doesn’t seem to indicate that they will laugh with joy, but rather, they will laugh that she is carrying a child and giving birth at such a elderly age. It would be a strange sight, seeing a very eldery women having a child.

Look at verse [7] again, “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.” She’s elated that she has borne this child to Abraham, and that God has fulfilled His promise of a child that will lead to a great nation and to great blessing that will spread throughout the earth.

We understand from all of Scripture that the birth of Isaac was the next step in God’s saving work that was leading up to Jesus. And the message is clear: God has done this. That’s the point, isn’t it? They had tried and tried. It was too hard. But in Genesis 18, when Sarah scoffed, God asked, rhetorically, “Is anything too hard for the LORD?” God would do it by His power alone, and that was the point.

As God fulfills His redemptive promise, human effort makes no contribution. And so no one may boast. Sarah could rejoice, but she could not boast. The LORD had done it.

There’s a wonderful statement that I’ve heard many times. I searched hard to find the source, and I could not. But I did find where pastor Steve Lawson uses it as he explains salvation. Lawson writes, “The central truth of God’s saving grace is succinctly stated in the assertion, “Salvation is of the Lord.” This strong declaration means that every aspect of man’s salvation is from God and is entirely dependent upon God.” And here’s the statement I was looking for. “The only contribution that we make is the sin that was laid upon Jesus Christ at the cross.”

The birth of Isaac was not just a thing God did for a man and woman one time. It was the fulfilling of God’s redemptive plan, a plan that would ultimately produce Jesus Christ.

We must not think that we contribute, or else we end up attempting to take some glory for ourselves, glory that we would be taking away from the Lord Jesus. If we do that, then we misunderstand both Him and ourselves. Do you think you contribute anything to salvation? If you did, you could boast about that. But human effort makes no contribution.

Now in these next verses the contrast with human effort becomes even clearer. Probably three years or so passes after the birth of Isaac. In those days, when a child made it through the dangers of infancy, the family would celebrate. The mortality rate was very high. And so, verse 8 says, “Abraham made a great feast on the day that Isaac was weaned.”

But notice verse 9, “Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, laughing.” The sense here is that Ismael mocked Isaac. Obviously, there would be jealousy in Ishmael and his mother, Hagar.

In Galatians 4 in the NT, Paul says that Ismael “persecuted” Isaac. There was animosity.

Abraham had done wrong by taking Hagar as a “wife.” She was never truly his wife; a man cannot be truly married to more than one woman.

Here you see the result of human effort to fulfill the promise of God: strife and destruction.

Sarah tells Abraham to send Hagar and Ismael away. And it seems that what this would do is not only remove them from the picture and from the household, but also, by giving them their freedom, Ishmael would no longer have legal rights to his inheritance as Abraham’s first born son.

Archeologists have discovered that this was done sometimes in the ancient world. A slave would be set free in exchange for any rights he or she had to property of any kind. Ishmael was the firstborn son of Abraham. There was no changing that.

And it was never going to work with all of them together. This is why, though it pained Abraham, God confirms that they should be set free and made to leave. Sarah was right when she said, verse 10, “Cast out this slave woman with her son, for the son of this slave woman shall not be heir with my son Isaac.”

The inheritor was the son conceived by the power of God. Ismael was a son conceived by human effort to fulfill the promise. The inheritance of Abraham was not for him.

And yet God is merciful to Hagar and Ishmael. In verse 13, God says that Ishmael will go on to have many descendants. He will live on. Look at verse [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.”

The translation from Hebrew is a bit challenging. The meaning of verse 13 is not that Abraham put Ishmael on her shoulder. Ishmael at this point was at least 15 years old. And “child” here could just as well be translated as “boy” or even “youth.”

So they set out with not much water and food, and they enter the desert and wander. She was probably making her way back to Egypt, where she was from. But the wording here indicates an aimlessness to their traveling. However, God had stated that Ismael would produce a great nation, so Abraham understood that God would make a way for Hagar and Ishmael.

Everywhere we look in our world today, we see the value and effects of incentives. People are motivated by something. They’re spurred on by the hope of receiving something. “Give us your email address and we’ll give you a discount.” “Shop in our store and we’ll reward you with points toward future purchases.” “Use our credit card and we’ll give you cash back.” Even the motivation to go to work or school is incentive-based. You work so you can get paid. You go to school so you can get a diploma, and then go get paid!

But think about this: how might an inheritance function as an incentive? Well, a person might behave a certain way or do certain things in order to secure the inheritance in the future.

“Inheritance” is a major theme throughout the Bible. And the apostle Peter is just one of the NT authors who talk about the inheritance that Christians receive. Listen to what he says: “Blessed be the God and Father of our Lord Jesus Christ! According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead, [4] to an inheritance that is imperishable, undefiled, and unfading, kept in heaven for you.”

Those who are born again, who trust in Jesus, have an inheritance as a result of being saved. But, you see, Peter says that God “caused us to be born again.” In other words, human effort made no contribution. And hand-in-hand with that is this truth: As God fulfills His redemptive promise, human effort secures no inheritance.

Back to Abraham, it was the child of God’s promise who was the heir, not the child of human efforts. That is clearly the point being made in Genesis 21; in fact, in the NT, in the book of Galatians, the apostle Paul explains that the Ishmael/Isaac situation should be understood in light of the law/grace situation that all Christians face.

For salvation, do you trust in yourself, or in God? Do you walk by sight, or by faith? Do you depend on human methods, or on God’s supernatural power? Do you rely on works, or on grace? Ishmael was born “of the flesh,” of the attempts of people to fulfill God’s redemptive promise. Isaac was born “of the Spirit,” of God’s supernatural fulfillment of His redemptive promise.

One of these receives the heavenly inheritance; one does not.

Don’t so many people feel they need to earn God’s love, earn God’s favor, earn God’s blessing? Earn, earn, earn. This takes nothing away from hard work in life, and it takes nothing away from our responsibility to obey God’s commands. But why do you obey?

Is your obedience an offering of love and honor given to the God who saved you by His grace, or do you obey just to get what you want from God? Why do you do what you do for God? What is your incentive?

Now in the final verses, we should think back to how it all began with Hagar and Ishmael. It started with Sarah wanting to hold Abraham’s child in her arms. The goal was life; but here, without God’s intervention, the end will be death.

They are making their way aimlessly through the desert, and they run out of water and bread. Physically, Ishmael is doing much worse than his mother. Perhaps as a teenage boy he need more sustenance than she did. And she believes that he is going to die. She leads him under a bush, and goes a far distance way, verse 16, “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.”

In Galatians 4, Paul says the Isaac vs.Ishmael situation should be understood figuratively as law vs. grace, as two opposing ways of understanding how to be made right with God. In light of that, consider this: relying on human effort to fulfill God’s redemptive promise is like trying to survive in a desert with no food or water.

This is the result of Abraham and Sarah’s human effort: this boy is going to die in the desert. But God intervenes. In verse 17, He tells her not to fear, He confirms that they will survive, He shows her that in His providence, there was a well nearby. They get a drink. They go on. And notice verse [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.

He was still the son of Abraham. He did not receive covenant promises, but He received mercy. And of course, many of His descendents would come to know the one true God one day, just as people have come to know Jesus from every nation of the world. But a life apart from the covenant of God is a wilderness life. That’s a desert life, leading to death.

As God fulfills His redemptive promise, human effort delivers only death.

I didn’t tell you how my guitar story turned out. Even though I had no hope of fixing this expensive instrument, I did know a young man living and working in Hartsville at the time, who fixed and built guitars. I showed it to him, knowing that if he couldn’t fix it, the guitar would likely be useless. Even if he did take on the job, I had no idea what he would charge, and if it would be worth it.

Well, long story short, this young man was building a business and hungry to show his skills. He took on the challenge and kept the guitar for about six months. Periodically, he would send me updates. It took tremendous time and patience. But for what ended up being just a few hundred dollars, he did what (to me) felt like a miracle. And that guitar sits in my home office today, fully intact, and it makes a beautiful sound.

I couldn’t fix it, but there was someone who could.

You don’t need to fix your sin problem; you need to lay your life in the hands of the only One who can fix it.

You don’t need to try to make yourself right with God; you need to humble yourself before the only One who can make you right with Him.

Human effort makes no contribution; Jesus Christ did all the work.

Human effort secures no inheritance, but through Jesus Christ, you get a future with God.

Human effort delivers only death; but the free gift of God is eternal life in Christ Jesus our Lord.

You don’t have to wander and die in the desert of life apart from God. Jesus says He is the Living Water; and He says He is the Bread of Life.

Jesus is your hope today if you are realizing that you haven’t really known God before now. And Jesus is the hope today for those of you who are trying to live for God and glorify Him.

We must look continually to Jesus for the encouragement to keep humbling ourselves, to keep repenting, to keep obeying, to keep standing for what is right in a world where so much is wrong.

Jesus Christ fixes our greatest problem: He brings us into the family of God! And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast – except in Jesus Christ.

Let’s bow together in prayer.