Abraham didn’t focus on his own impotence and say, “It’s hopeless. This hundred-year-old body could never father a child.” Nor did he survey Sarah’s decades of infertility and give up. He didn’t tiptoe around God’s promise asking cautiously skeptical questions. He plunged into the promise and came up strong, ready for God, sure that God would make good on what he had said. That’s why it is said, “Abraham was declared fit before God by trusting God to set him right.” But it’s not just Abraham; it’s also us! The same thing gets said about us when we embrace and believe the One who brought Jesus to life when the conditions were equally hopeless. The sacrificed Jesus made us fit for God, set us right with God.

Don’t suppose for a moment, though, that God’s Word has malfunctioned in some way or other. The problem goes back a long way. From the outset, not all Israelites of the flesh were Israelites of the spirit. It wasn’t Abraham’s sperm that gave identity here, but God’s promise. Remember how it was put: “Your family will be defined by Isaac”? That means that Israelite identity was never racially determined by sexual transmission, but it was God-determined by promise. Remember that promise, “When I come back next year at this time, Sarah will have a son”?

Tell me now, you who have become so enamored with the law: Have you paid close attention to that law? Abraham, remember, had two sons: one by the slave woman and one by the free woman. The son of the slave woman was born by human plotting; the son of the free woman was born by God’s promise. This illustrates the very thing we are dealing with now. The two births represent two ways of being in relationship with God. One is from Mount Sinai in Arabia. It corresponds with what is now going on in Jerusalem—a slave life, producing slaves as offspring. This is the way of Hagar. In contrast to that, there is an invisible Jerusalem, a free Jerusalem, and she is our mother—this is the way of Sarah. Remember what Isaiah wrote: Rejoice, barren woman who bears no children, shout and cry out, woman who has no birth pangs, Because the children of the barren woman now surpass the children of the chosen woman. Isn’t it clear, friends, that you, like Isaac, are children of promise? In the days of Hagar and Sarah, the child who came from faithless plotting (Ishmael) harassed the child who came—empowered by the Spirit—from the faithful promise (Isaac). Isn’t it clear that the harassment you are now experiencing from the Jerusalem heretics follows that old pattern? There is a Scripture that tells us what to do: “Expel the slave mother with her son, for the slave son will not inherit with the free son.” Isn’t that conclusive? We are not children of the slave woman, but of the free woman.

By faith, barren Sarah was able to become pregnant, old woman as she was at the time, because she believed the One who made a promise would do what he said. That’s how it happened that from one man’s dead and shriveled loins there are now people numbering into the millions. * * *

Cultivate Inner Beauty

The same goes for you wives: Be good wives to your husbands, responsive to their needs. There are husbands who, indifferent as they are to any words about God, will be captivated by your life of holy beauty. What matters is not your outer appearance—the styling of your hair, the jewelry you wear, the cut of your clothes—but your inner disposition. Cultivate inner beauty, the gentle, gracious kind that God delights in. The holy women of old were beautiful before God that way, and were good, loyal wives to their husbands. Sarah, for instance, taking care of Abraham, would address him as “my dear husband.” You’ll be true daughters of Sarah if you do the same, unanxious and unintimidated.