⁷ And only some of Abraham’s descendants are true children of Abraham. This is what God said to Abraham: “Your true descendants will be those who come through Isaac.”^{[a] 8} This means that not all of Abraham’s descendants are God’s true children. Abraham’s true children are those who become God’s children because of the promise he made to Abraham. ⁹ Here is what God said in that promise: “About this time next year I will come back, and Sarah will have a son.”^[b]