His faith did not weaken when he thought about his own body (which was already as good as dead now that he was about a hundred years old) or about Sarah's inability to have children,

For this is the language of the promise: "At this time I will return, and Sarah will have a son."

By faith Sarah, even though she was old and barren, received the strength to conceive, because she was convinced that the one who had made the promise was faithful.

just as Sarah obeyed Abraham and called him lord. You have become her daughters by doing good and by not letting anything terrify you.