Genesis 18:14 (KJV)

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?

And the LORD said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old?

Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh.

And the men rose up from thence, and looked toward Sodom: and Abraham went with them to bring them on the way.

And the LORD said, Shall I hide from Abraham that thing which I do;

Seeing that Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him?

For I know him, that he will command his children and his household after him, and they shall keep the way of the LORD, to do justice and judgment; that the LORD may bring upon Abraham that which he hath spoken of him.