Genesis 18:9-14

Then they said to him, “Where is Sarah your wife?” And he said, “There, in the tent.” He said, “I will surely return to you at this time next year; and behold, Sarah your wife will have a son.” And Sarah was listening at the tent door, which was behind him. Now Abraham and Sarah were old, advanced in age; Sarah was past childbearing. Sarah laughed to herself, saying, “After I have become old, shall I have pleasure, my lord being old also?” And the LORD said to Abraham, “Why did Sarah laugh, saying, ‘Shall I indeed bear a child, when I am so old?’ Is anything too difficult for the LORD? At the appointed time I will return to you, at this time next year, and Sarah will have a son.”