Genesis 18:8-12

And he took butter, and milk, and the calf which he had dressed, and set it before them; and he stood by them under the tree, and they did eat.

And they said unto him, Where is Sarah thy wife? And he said, Behold, in the tent.

And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard it in the tent door, which was behind him.

Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women.

Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also?