Jesus: From Genesis to Revelation

Day 5: Week 10 Day 5

Reading

Historical Context

God now turns his attention to Sarai, and the first act is a renaming. “As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her name” (17:15). The shift from Sarai to Sarah is subtle in English but significant in Hebrew. Both forms are related to the root sarah (princess, noblewoman), but the change from the older form to the standard one may signal a transition from a private, archaic identity to a public, covenantal one. More importantly, God speaks a blessing over her that matches the blessing spoken over Abraham: “I will bless her, and moreover, I will give you a son by her. I will bless her, and she shall become nations; kings of peoples shall come from her” (17:16). Sarah is not a passive vessel. She is a covenantal partner – blessed, named, and promised a role in the story that is hers, not merely her husband’s.

Abraham’s response is visceral. “Then Abraham fell on his face and laughed” (vayyitschaq) (17:17). The Hebrew verb tsachaq – to laugh – will become the name of the promised child. Abraham’s laughter is complex. The text does not explicitly condemn it, nor does it sanitize it. His internal monologue reveals the source: “Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?” The questions are not rhetorical. They are biological. Abraham is doing the arithmetic, and the arithmetic does not work. Post-menopausal conception was as impossible in the ancient world as it is today. Abraham is not being faithless – the man who believed God under the stars has not abandoned trust. He is being human. He is laughing because the promise has exceeded the category of difficulty and entered the category of absurdity. And God, rather than rebuking the laughter, writes it into the child’s name. Yitschaq – “he laughs.” Every time Abraham will call his son, he will be reminded that God’s promises provoke laughter before they produce faith.

Abraham then intercedes for Ishmael: “Oh that Ishmael might live before you!” (17:18). The plea is a father’s heart speaking. Abraham has spent thirteen years raising this boy. He loves him. He wants God’s blessing on the son he already has, not a hypothetical son who has not yet been conceived. God’s response is both generous and precise. “As for Ishmael, I have heard you. Behold, I have blessed him and will make him fruitful and multiply him greatly. He shall father twelve princes, and I will make him into a great nation” (17:20). The blessing is real and substantial – twelve princes, a great nation, fruitfulness beyond measure. But then the qualifier: “But I will establish my covenant with Isaac, whom Sarah shall bear to you at this time next year” (17:21). The covenant – berith – runs through Isaac alone. Ishmael is blessed but not covenanted. He is loved but not chosen for the particular role of carrying the promise line to its fulfillment. The distinction is not about Ishmael’s worth. It is about God’s sovereign election – the narrowing of the promise to one line, one family, one son, until it reaches the one Son through whom all nations will be blessed.

The chapter closes with immediate obedience. “That very day Abraham was circumcised, and Ishmael his son” (17:23). Abraham is ninety-nine. Ishmael is thirteen. Every male in the household – born in the house or bought with money – receives the covenant sign on the same day. The speed of compliance is striking. Whatever laughter Abraham offered at the announcement of Isaac, his response to the command of circumcision is unhesitating. He does not wait, negotiate, or ask for clarification. The verb bemetsem hayom hazzeh – “on that very day” – emphasizes the immediacy. Faith and obedience, in the biblical pattern, are not opposites of laughter. They coexist. Abraham laughs at the promise and obeys the command in the same chapter, on the same day. The God who provokes incredulity also commands action, and Abraham gives him both.

The detail that Ishmael is circumcised at thirteen is significant. In later Islamic tradition, circumcision at thirteen (or at puberty) becomes normative, tracing its practice to Ishmael’s example in this very passage. The divergence between Israelite circumcision on the eighth day and Ishmaelite circumcision at puberty reflects the divergence of the two covenant lines – one marked in infancy before consent, the other marked at the threshold of adulthood. Both lines trace back to this single day in Abraham’s household, and both carry the mark of a covenant that began with a ninety-nine-year-old man obeying a God who had just made him laugh.

Christ in This Day

The birth of Isaac is the first in a series of impossible births that form the backbone of biblical theology and culminate in the incarnation of Christ. A barren, post-menopausal woman conceives by divine promise – not by natural means, not by human strategy (that was Hagar’s role), but by the direct intervention of God who speaks life into biological impossibility. The pattern will repeat: Rebekah is barren until God opens her womb (Genesis 25:21). Rachel is barren until God remembers her (Genesis 30:22). Hannah weeps for years before Samuel is given (1 Samuel 1:19-20). Elizabeth, “advanced in years,” conceives John the Baptist (Luke 1:7, 36). Each barren womb that opens by divine command is a smaller rehearsal for the ultimate impossible birth – a virgin conceives, and the son she bears is not merely a child of promise but the Promise himself, “Immanuel, God with us” (Matthew 1:23). The angel’s words to Mary echo across every barren womb in Scripture: “For nothing will be impossible with God” (Luke 1:37) – the same word spoken over Sarah’s closed womb four millennia earlier.

Paul makes the Isaac-Christ connection explicit in Romans 4:17-22. He describes Abraham as believing in “the God who gives life to the dead and calls into existence the things that do not exist” (Romans 4:17). The language is simultaneously about Isaac’s birth and about the resurrection of Christ. Abraham’s body was “as good as dead” (nenekromenon) and Sarah’s womb was “dead” (nekrosin) – yet from this double death, God brought life. The God who brings a child from a dead womb is the same God who brings a Son from a sealed tomb. Isaac’s birth is resurrection in miniature. And Abraham’s faith in the promise of Isaac is, Paul argues, the same faith that justifies everyone who believes “in him who raised from the dead Jesus our Lord, who was delivered up for our trespasses and raised for our justification” (Romans 4:24-25). The stars Abraham counted, the son Sarah bore, and the Savior God raised are all connected by the same thread: a God who specializes in bringing life from death, existence from nothing, and laughter from the impossible.

The laughter itself carries Christological weight. Abraham laughs at the absurdity of the promise. Sarah will laugh when she overhears it (Genesis 18:12). And God names the child “Laughter” – Yitschaq – not as a rebuke but as a memorial. The God of the covenant does not erase human incredulity. He redeems it. He takes the laugh that expressed impossibility and transforms it into the name of the child who proves that nothing is impossible with God. There is a theological laughter that runs through the gospel – the joy of the impossible made actual, the delight of those who discover that what they thought could never happen has happened. Mary’s Magnificat is this laughter set to music: “He has scattered the proud… he has filled the hungry with good things” (Luke 1:51-53). The resurrection itself is the ultimate Yitschaq – the moment when death, the final impossibility, is overturned, and the laughter of Easter morning echoes backward through every barren womb, every dead body, every sealed tomb, all the way to a ninety-nine-year-old man falling on his face in the dust and laughing because God had just said the most impossible thing he had ever heard.

Key Themes

Connections

Old Testament Roots

Sarah’s promised motherhood connects to the broader biblical theme of barren women who become mothers of pivotal figures: Rebekah (Genesis 25:21), Rachel (Genesis 30:22), the mother of Samson (Judges 13:2-3), Hannah (1 Samuel 1:2), and the Shunammite woman (2 Kings 4:14-17). Each barren womb is a stage on which God demonstrates that the children who carry his purposes forward are gifts, not products of human fertility. The promise that “kings of peoples shall come from her” (17:16) will be fulfilled through the royal line of Judah – David, Solomon, and ultimately Jesus, “the son of David, the son of Abraham” (Matthew 1:1).

New Testament Echoes

Romans 4:17-22 describes Abraham’s faith as trust in the God who “gives life to the dead and calls into existence the things that do not exist” – language that applies equally to Isaac’s birth and Christ’s resurrection. Hebrews 11:11-12 credits Sarah herself with faith: “By faith Sarah herself received power to conceive, even when she was past the age, since she considered him faithful who had promised.” Luke 1:36-37 – the angel’s announcement to Mary that the barren Elizabeth has conceived – explicitly connects the impossible births of the Old Testament to the virgin birth: “For nothing will be impossible with God.” Matthew 1:1-2 opens the genealogy of Jesus with “Abraham… the father of Isaac” – the very line promised in Genesis 17.

Parallel Passages

Isaiah 51:1-2 calls Israel to “look to Abraham your father and to Sarah who bore you; for he was but one when I called him, that I might bless him and multiply him.” Isaiah 54:1 – “Sing, O barren one, who did not bear” – is applied by Paul to the church in Galatians 4:27, the community born of promise rather than flesh. Romans 9:7-9 cites Isaac specifically: “Through Isaac shall your offspring be named… it is not the children of the flesh who are the children of God, but the children of the promise are counted as offspring.”

Reflection Questions

  1. Abraham laughs at God’s promise, and God names the child “Laughter.” What does it reveal about God’s character that he does not rebuke human incredulity but redeems it – writing it into the story rather than editing it out?

  2. Abraham pleads for Ishmael: “Oh that Ishmael might live before you!” God blesses Ishmael generously but establishes the covenant through Isaac alone. How do you hold together God’s generosity toward all people and his sovereign choice to work through particular people and particular lines?

  3. The pattern of impossible births in Scripture – Sarah, Rebekah, Rachel, Hannah, Elizabeth, Mary – reveals a God who consistently brings life from barrenness and death. Where in your life do you need to trust the God who “gives life to the dead and calls into existence the things that do not exist” (Romans 4:17)?

Prayer

Father, you are the God who makes ninety-year-old women laugh and then names the child after the laughter. You are the God who blesses Ishmael and covenants with Isaac, who is generous beyond measure and sovereign beyond question. We stand with Abraham in the dust, faces down, laughing at promises we cannot explain and obeying commands we do not fully understand. Forgive us when our laughter is the laughter of unbelief rather than the laughter of wonder. Teach us to trust the God who gives life to the dead – who brought Isaac from a barren womb, who brought Jesus from a sealed tomb, and who brings new life from the deadness of our own hearts. We thank you that the line of promise runs from Abraham through Isaac through David to Jesus, and that by faith in Christ we are written into that line – children of promise, born not of the flesh but of the Spirit, named not by our circumstances but by your covenant. In the name of Jesus, the son of Abraham, the seed of promise, the resurrection and the life. Amen.