Genesis 18:10-13

And he said, I will certainly return unto thee when the season cometh round; and, lo, Sarah thy wife shall have a son. And Sarah heard in the tent door, which was behind him. Now Abraham and Sarah were old, and well stricken in age; it had ceased to be with Sarah after the manner of women. And Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also? And Jehovah said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, who am old?