In Genesis 20–21, promises delayed finally arrive. Isaac is born. Joy erupts. But not without complication. Abraham’s fears resurface. Hagar and Ishmael are cast out. God protects both Sarah and Hagar, both Isaac and Ishmael. This Mile Marker explores the faithfulness of God through human fear, failure, and delay. Even when promises seem lost, laughter still breaks through. Grace shows up in deserts, dreams, and delivery rooms. Let these chapters remind you: it’s never too late for joy.
“The Lord kept His word and did for Sarah exactly what he had promised.”
Genesis 21:1 (NLT)Promises delayed often become promises doubted. Abraham had believed, followed, sacrificed—but still had no son. Now, as old age overtakes them both, the promise comes again.
But first—another stumble. Abraham lies about Sarah in Gerar (Gen 20:1-2), fearing for his life. Again, God intervenes. Again, grace covers fear. And then, suddenly—laughter breaks through the long silence.
“The Lord kept His word” (Gen 21:1). Isaac is born. The impossible happens. And the name itself—“He laughs”—becomes a monument to mercy that defied the odds.
Genesis 20 begins not with a miracle, but with a repeated failure. Once again, Abraham, fearing for his life, tells a foreign king that Sarah is his sister (Gen 20:2). It’s the same lie he told in Egypt. Time has passed, faith has grown—but the old instinct to self-protect resurfaces under pressure. And yet, God intervenes.
He appears to Abimelek in a dream, revealing the truth and warning him not to touch Sarah (Gen 20:3-7). The rebuke is firm—but so is the protection. God shields the promise, even when the promise-carrier fails. Arthur Pink writes, “How marvelously patient is God with His erring children! And how blessedly does His grace triumph over our failures!”1
Then, at long last, the silence breaks. Sarah conceives. The impossible occurs. The child they had laughed at in disbelief is born in joy. Isaac enters the world not through effort, but through promise—evidence that God's timing is perfect, even when it feels overdue (Gen 21:1-3).
Sarah, once bitter and barren, now bursts into laughter: “God has brought me laughter. All who hear will laugh with me” (Gen 21:6). Her story reminds us that divine joy often rises from places long closed off by despair.
But joy does not erase history. Ishmael, now a teenager, mocks the celebration (Gen 21:9). Sarah, fiercely protective of Isaac, demands that Abraham send Hagar and Ishmael away. It’s a painful scene—complex and emotionally charged.
Abraham is grieved, but God tells him to listen to Sarah—assuring him that Ishmael, too, will become a great nation (Gen 21:12-13). This moment doesn't glorify division—it acknowledges the sorrow of shortcuts. Sometimes the cost of past choices resurfaces when promise and flesh collide.
In the ancient Near East, lineage was everything. Children were not just a blessing—they were security, legacy, survival. A barren woman was considered cursed. A man without an heir was a man whose name would die with him.
And yet, Abraham and Sarah are chosen precisely in their lack. God builds His covenant on a foundation the world would have dismissed. The delay wasn’t a punishment—it was a canvas for glory.
We may not count heirs, but we know what it is to wait. We know the ache of unfulfilled promise, the fatigue of unanswered prayer. In our culture of instant gratification, waiting feels like failure.
But the message of Genesis 20–21 is that delay is not denial. God’s faithfulness doesn’t operate on our timelines—and His mercy often shows up just when we’re ready to give up. Laughter, too, has a timing. And it is never late when it is born of promise.
Abraham’s deception in Gerar isn’t a new sin—it’s a recycled one. He had done the same thing years earlier in Egypt (Gen 12:11-13). We don't always fall in new ways—we often return to old cracks in our character. Fear remains a powerful force, even for the faithful.
Yet God does not abandon him. Instead, He steps into the failure, defends Sarah, and restores the situation—not because Abraham deserves it, but because God is committed to the promise. Grace is not permission to fall, but power to rise again.
The joy of Isaac’s birth exposes the unresolved pain of Ishmael’s existence. Sarah sees Ishmael’s mocking and reacts with protective force (Gen 21:9-10). Her words sound harsh, but they touch on a deeper truth: the son of works and the son of promise cannot share the same inheritance.
This is more than family drama—it’s spiritual symbolism. Paul later uses this moment to contrast law and grace (Galatians 4:22-31). Spurgeon comments, “The child of the bondwoman may be born after the flesh, but the child of the freewoman is born after the promise; and between these two there is an inevitable opposition.”2
Cast out into the dry places, Hagar and Ishmael come to the brink of death. She places her boy under a bush and weeps, convinced it’s over (Gen 21:15-16). But God hears the cry—not just of Hagar, but of the boy (Gen 21:17). And once again, He provides.
This scene reminds us: God doesn’t just preserve the covenant line—He sees the overlooked. He hears those who were never meant to carry the promise, yet still matter in His mercy.
Isaac’s name means “he laughs”. It’s not just a private joy—it’s a testimony that God keeps His promises even after hope has grown old. Isaac becomes a walking witness that faith is not foolish, even when delayed for decades.
His birth was promised, postponed, and then delivered in power. This foreshadows another miraculous child—born not by human striving, but by divine intervention. Jesus, too, entered a world that had stopped expecting Him.
Isaac’s life sets up a profound parallel. He is the beloved son, born by promise, who will soon be led up a mountain in Genesis 22. There, he becomes a picture of willing surrender and substitution—a shadow of the Son who would later carry a cross up Golgotha.
Promise, sacrifice, and provision are woven together. Isaac prefigures Christ not only in birth, but in the role he plays in the unfolding story of redemptive grace.
Ishmael’s salvation in the wilderness reminds us that God's mercy extends beyond chosen lines. The covenant flows through Isaac, but the compassion of God follows Ishmael. A well opens. A nation begins. Even castaways become part of the story.
A.W. Tozer once wrote, “We please God most not by frantically trying to make ourselves good but by throwing ourselves into His arms with all our imperfections and believing that He understands everything—and still loves us.”3
Maybe it’s been years since you first heard God speak a promise over your life. And maybe now, like Abraham and Sarah, you find yourself older, wearier, and more skeptical than you ever imagined. Waiting changes us—it stretches faith, exposes fear, and tests what we really believe about God’s character.
But the story of Isaac’s birth reminds us that God is not slow—He’s precise. The promises of God do not expire with time. They deepen. And when they arrive, they bring joy that makes sense only in light of the long delay.
Sarai's response to Hagar reflects something uncomfortable in us all. In our desperation to protect what God has given, we sometimes forget the dignity of others in the story. It is possible to be part of the promise and still be unjust.
This chapter invites us to examine how we treat the Hagars and Ishmaels in our lives—the ones whose existence complicates our clean narratives. God did not erase them. He heard them. He blessed them. So must we.
Abraham stumbled in familiar ways. Sarah laughed in disbelief. Hagar wept in exile. But none of these things disqualified them from the mercy of God. If you’ve failed again, doubted again, wept again—you are not outside His redemptive reach.
This chapter does not offer a polished ending. But it does offer a laugh—a child named Isaac whose birth defied biology, fear, and human timing. That laugh belongs to you too, if you will trust the One who always shows up—eventually, and exactly.
God’s timing stretches us. It refines us. But it never fails us. Abraham’s missteps didn’t cancel the promise. Sarah’s laughter, once cynical and bitter, became joyful and radiant. That shift didn’t happen overnight—it happened in the long wait, the dry years, the repeated disappointments.
Isaac’s name reminds us: what once seemed laughable can become sacred. God transforms disbelief into delight, and delay into deliverance. The absurd becomes assurance. The silence becomes song. And the womb once closed becomes the vessel of joy.
Even when we fear, falter, and forget—God is not done. His covenant doesn’t rely on our consistency, but on His character. His word does not return void. His mercy does not forget the cast out. His love does not diminish with age or distance or delay.
So if you find yourself still waiting, still aching, still wondering if your moment will come—remember this: The promise was not just to Abraham and Sarah. It was through them, for you. And God never fails what He has sworn to finish.
What has God spoken over your life that hasn’t come to pass yet? Have you stopped praying for it? Have you started laughing bitterly instead of hopefully?
Hagar and Ishmael were not part of the chosen line—but God heard their cries in the wilderness. Do you see yourself in their exile more than in Sarah’s joy?
Abraham repeated an old sin. Sarah laughed in disbelief. Yet neither were rejected. God used them anyway. Do you believe He can still use you?
Isaac means “He laughs.” His very existence is a reminder that joy isn’t just possible—it’s promised. But sometimes, we need to give ourselves permission to feel it.
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Scripture quotations marked (NLT) are taken from the Holy Bible, New Living Translation, copyright © 1996, 2004, 2015 by Tyndale House Foundation. Used by permission of Tyndale House Publishers, Carol Stream, Illinois 60188. All rights reserved.
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