The Divine No and the Covenant of Laughter Text: Genesis 17:15-22
Introduction: God's Prerogative and Our Plans
We live in an age that despises the word "no." Our entire culture is built on the sandy foundation of "my will be done." We are told from every quarter that our desires are sovereign, our plans are paramount, and our feelings are the final arbiter of truth. We want a god, if we want one at all, who is a celestial butler, a divine affirmer, one who exists to bless our pre-approved agendas. We want a god who says, "Yes, and how high?"
But the God of Abraham is not that kind of god. He is not a cosmic vending machine, and He does not rubber-stamp the schemes of men, even the schemes of His chosen friends. The God of Scripture is the sovereign Lord of all creation, and His purposes are not subject to our review or approval. He is the potter, we are the clay, and He does not consult the clay about the shape of the vessel. This is a truth that our generation finds offensive, but it is the only truth that can save us. God's sovereign prerogative is not a threat to our freedom; it is the very foundation of it. His "no" is often a greater mercy than His "yes."
In our text today, we come to a pivotal moment in the life of Abraham. God has just renewed His covenant, changed Abram's name to Abraham, and instituted the sign of circumcision. The promises are grand, cosmic, and earth-shattering. But then God narrows the focus with a laser-like intensity onto the withered womb of a ninety-year-old woman. And in this intensely personal and seemingly impossible promise, we see the collision of divine sovereignty and human reasoning. We see Abraham, the great man of faith, fall on his face and laugh. We see him offer God a reasonable, alternative plan. And we see God, in His glorious and unbending purpose, deliver one of the most important sentences in redemptive history: "No, but Sarah your wife will bear you a son."
This passage is about more than just the parentage of Isaac. It is about the nature of the covenant of grace. It is about the difference between the work of the flesh and the work of the Spirit. It is about how God establishes His kingdom not through human ingenuity and common sense, but through divine power and resurrection life. It is about the laughter of incredulity being transformed into the laughter of joy. And it teaches us that our most reasonable plans are often the greatest obstacles to God's most glorious purposes.
The Text
Then God said to Abraham, “As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her name. And I will bless her, and indeed I will give you a son by her. Then I will bless her, and she shall be a mother of nations; kings of peoples will come from her.” Then Abraham fell on his face and laughed and said in his heart, “Will a son be born to a man one hundred years old? And will Sarah, who is ninety years old, bear a son?” And Abraham said to God, “Oh that Ishmael might live before You!” But God said, “No, but Sarah your wife will bear you a son, and you shall call his name Isaac; and I will establish My covenant with him for an everlasting covenant for his seed after him. As for Ishmael, I have heard you; behold, I will bless him and will make him fruitful and will multiply him exceedingly. He shall become the father of twelve princes, and I will make him a great nation. But My covenant I will establish with Isaac, whom Sarah will bear to you at this season next year.” So He finished talking with him, and God went up from Abraham.
(Genesis 17:15-22 LSB)
The Princess and the Promise (v. 15-16)
We begin with God's specific word concerning Sarai.
"Then God said to Abraham, 'As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her name. And I will bless her, and indeed I will give you a son by her. Then I will bless her, and she shall be a mother of nations; kings of peoples will come from her.'" (Genesis 17:15-16)
Just as God renamed Abram to Abraham, signifying his role as the father of a multitude, He now renames Sarai. The name Sarai meant "my princess," which has a personal, possessive sense. But God changes her name to Sarah, which means "princess." He removes the personal pronoun. She is not just Abraham's princess; she is the princess, a royal mother in a universal sense. This is not a demotion but a massive promotion. Her identity is no longer defined solely by her relationship to her husband but by her role in God's global, covenantal purpose.
To name something is to exercise authority over it. God gave Adam the task of naming the animals, a task of delegated dominion. Here, God names the matriarch of the covenant people, asserting His absolute sovereignty over her life, her body, and her destiny. This is a direct assault on the pagan worldview where fertility was governed by capricious, localized deities. The God of Abraham is the Lord of the womb, even a womb that has been dead for decades.
And the promise attached to the name is staggering. "I will bless her... I will give you a son by her... she shall be a mother of nations; kings of peoples will come from her." Notice the emphatic repetition: "I will bless her... Then I will bless her." This is a sovereign, unilateral declaration. The blessing does not depend on Sarah's biological condition, her age, or her faith. It depends entirely on the character and power of the God who speaks. The promise is not just for a son, but for a royal lineage. From this barren, ninety-year-old woman will come kings. This is the grammar of the gospel: God brings life out of death, and royalty out of ruin.
The Laughter of Honest Unbelief (v. 17-18)
Abraham's response is immediate, physical, and entirely human.
"Then Abraham fell on his face and laughed and said in his heart, 'Will a son be born to a man one hundred years old? And will Sarah, who is ninety years old, bear a son?' And Abraham said to God, 'Oh that Ishmael might live before You!'" (Genesis 17:17-18)
First, he fell on his face. This is the posture of worship, of reverence, of submission. Even in his astonishment, he acknowledges who is speaking. But then, he laughed. We should not be too quick to condemn this laughter. The New Testament commends Abraham for his faith, telling us he "did not waver in unbelief" (Romans 4:20). This was not the cynical, mocking laughter of Sarah in the next chapter. This was the laughter of incredulity, the gasp of a man whose categories have just been gloriously shattered. It was the laughter of a man who believed God could do anything, but was still floored by the sheer, joyful absurdity of what God proposed to do.
His internal monologue is a simple calculation of the biological impossibilities. He is a century old. She is ninety. This is not just unlikely; it is, by every law of nature, impossible. And because it seems impossible, Abraham, in his very next breath, offers God a perfectly reasonable Plan B. "Oh that Ishmael might live before You!"
This is not a rejection of God's promise so much as an attempt to help God fulfill it in a sensible way. Abraham already has a son, Ishmael. He is a teenager, strong and alive. He is the product of Abraham's own efforts, his own attempt to "help" God's plan along back in chapter 16. From a human perspective, making Ishmael the heir is the logical path. It's practical. It's efficient. It avoids the whole messy business of geriatric pregnancy. Abraham is essentially saying, "Lord, I appreciate the thought, but I've already taken care of this. Let's just ratify the arrangement we already have." He is offering God the work of his own hands, the fruit of the flesh, as the vehicle for the covenant of grace.
The Divine Correction: No, But... (v. 19-21)
God's response is swift, sharp, and absolute. It is a flat refutation of Abraham's well-intentioned pragmatism.
"But God said, 'No, but Sarah your wife will bear you a son, and you shall call his name Isaac; and I will establish My covenant with him for an everlasting covenant for his seed after him.'" (Genesis 17:19)
This "No, but..." is one of the most important theological statements in the Bible. God rejects the reasonable, humanly-produced son in favor of the impossible, divinely-produced son. Why? Because the covenant of grace cannot be established on the works of man. It must be established on the miraculous, life-from-the-dead power of God alone. Paul makes this the central point of his argument in Galatians. Ishmael is the son born "according to the flesh," while Isaac is the son born "through promise" (Galatians 4:23). The two sons represent two covenants: one of law and works that leads to slavery, and one of grace and promise that leads to freedom.
God insists on doing it the impossible way so that no one can mistake who gets the glory. If Ishmael had been the heir, Abraham could have always taken a little bit of the credit. But with Isaac, born to a dead womb and a hundred-year-old man, all the glory goes to God. This is the pattern of salvation. God does not accept our Ishmaels, our good works, our religious efforts, our attempts to make ourselves acceptable to Him. He says "No" to all of it. "No, but... my Son." Salvation is not a cooperative effort. It is a divine accomplishment.
God even names the child. "You shall call his name Isaac." The name Isaac means "he laughs." God takes Abraham's laughter of astonishment and consecrates it. He embeds the memory of this impossible promise into the very name of the child. Every time Abraham called his son, he would be reminded of his own incredulity and God's faithfulness. God's promises are so sure that He can name the child a year before he is even conceived.
God is gracious to Abraham's concern for Ishmael. He hears Abraham's fatherly heart. He promises to bless Ishmael, to make him fruitful, to make him a great nation with twelve princes. Ishmael will receive common grace, earthly blessings. But the covenant, the line of redemption, the everlasting promise, that is reserved for Isaac alone. "But My covenant I will establish with Isaac." This is the doctrine of election in miniature. God makes a distinction. He blesses many, but His saving, covenantal purpose runs through a specific, chosen line. This is not arbitrary; it is purposeful. The line of Isaac will lead to Christ.
God's Word and Abraham's Obedience (v. 22)
The scene concludes with a simple, majestic statement.
"So He finished talking with him, and God went up from Abraham." (Genesis 17:22)
The conversation is over. God has spoken, and there is no more room for negotiation or alternative plans. The word of the Lord is final. God's departure signifies that the terms have been set. All that remains is for Abraham to believe and obey, which the subsequent verses show he did immediately. The divine word creates the reality, and the man of faith responds by aligning his life with that new reality.
Conclusion: Your Ishmael and God's Isaac
The story of Abraham, Ishmael, and Isaac is your story. In our fallen state, all we can produce is Ishmael. We are masters at generating works of the flesh. We build our lives on sensible plans, self-help strategies, religious observances, and moral efforts. We take these things, the fruit of our own strength, and we present them to God, saying, "Oh that Ishmael might live before You!" We ask God to bless our efforts, to accept our work, to ratify our plans for self-salvation.
And the gospel is the glorious, liberating, and sometimes infuriating word of God that says, "No." No, your efforts are not enough. No, your righteousness is as filthy rags. No, your sensible plans cannot accomplish my eternal purpose. God rejects our Ishmael, not because He is cruel, but because He loves us too much to let us settle for a covenant of flesh. He has something infinitely better.
He says, "No, but..." And that "but" is followed by the promise of His Son, Jesus Christ. He is the true Isaac, the child of promise, miraculously conceived and brought forth from the dead womb of the grave. We cannot contribute to His work any more than Abraham could contribute to the conception of Isaac. All we can do is fall on our faces, laugh with astonished joy, and receive the gift.
God's covenant is not with our Ishmael, but with His Isaac. He will bless our earthly efforts with common grace, but salvation, the everlasting covenant, is found in Christ alone. The central question for each of us, then, is this: are you still trying to get God to accept your Ishmael? Or have you heard His gracious "no," and rested entirely in the finished work of His Isaac, the Lord Jesus Christ, in whom all the promises of God are Yes and Amen?