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”?