Twenty-five years sit between the promise and this chapter. God first told Abraham he would become a great nation when Abraham was seventy-five and childless. Now the wait ends in a single verse. 1"The LORD visited Sarah as he had said, and the LORD did to Sarah as he had promised." Two clauses do the same work twice, and a third follows in verse 2, "at the time of which God had spoken to him." Three ways, in two verses, of saying that God said it would happen and it happened.
The birth is stated as plainly as anything in Scripture. 5"Abraham was a hundred years old when his son Isaac was born to him." A hundred-year-old father and a ninety-year-old mother make up the whole miracle. On the eighth day Abraham circumcised his son as God had commanded in Genesis 17. Ishmael was circumcised at thirteen, old enough to remember the wait. Isaac carries the same mark from eight days old, before he has done anything to earn it. The sign of the covenant lands on him as pure gift, which is where every child of promise stands.
Then comes the name, and with it a thread the story has been pulling since chapter 17. Isaac means "he laughs." Abraham had fallen on his face and laughed when God first promised the son. Sarah had laughed to herself behind the tent flap, then denied it out of fear. Now the boy those two laughs produced has been born, and Sarah says something entirely different. 6"God has made laughter for me; everyone who hears will laugh over me." Same root as her son's name. The laughter is the same word with a new meaning. What was a private, guilty reflex has become a public invitation, and she wants everyone who hears the story to laugh with her.
She goes on. 7"Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age." She seems to be turning the fact over to make sure it happened, a woman her age nursing a child. It is the longest speech Sarah gets in Genesis, and she spends it on wonder.
That claim is bigger than Sarah knew. Paul reaches back to this story to say what every believer is. 28"Now you, brothers, like Isaac, are children of promise" (Galatians 4:28). Ishmael was born because two people decided to solve the problem themselves. Isaac was born the way Paul says every believer is born, against the odds, on God's timing, by a promise nothing in the natural order could have produced. We did not talk ourselves into faith any more than Sarah talked herself into a child at ninety. Someone had to visit us the way the LORD visited Sarah.
Abraham and Sarah did not wait well the whole way through. Hagar and Ishmael are proof enough, and so is the lie about Sarah being his sister, told twice. The promise stood anyway. Hebrews says of Sarah that she "considered him faithful who had promised" (Hebrews 11:11). That is a smaller claim than it sounds, and a truer one. She trusted the character of the one who spoke over her own arithmetic. Whatever you are still waiting on, the promise rests on him.
Prayer
Father, we have laughed the wrong laugh before, the kind that comes from doubting what you said, and we have hidden it as Sarah did. Thank you that our doubt never changed what you had promised. Thank you that we too are children born of your word. Teach us to wait as Sarah finally learned to laugh, trusting your character over our sense of what is possible. In Jesus' name, amen.