Genesis

And Abraham was ninety years old and nine, when he was circumcised in the flesh of his foreskin.

And Ishmael his son was thirteen years old, when he was circumcised in the flesh of his foreskin.

In the selfsame day was Abraham circumcised, and Ishmael his son.

And all the men of his house, born in the house, and bought with money of the stranger, were circumcised with him.

And Abram fell on his face: and God talked with him, saying,

As for me, behold, my covenant is with thee, and thou shalt be a father of many nations.

Neither shall thy name any more be called Abram, but thy name shall be Abraham; for a father of many nations have I made thee.

And I will make thee exceeding fruitful, and I will make nations of thee, and kings shall come out of thee.

And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee.

And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations.

And the LORD appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day;

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?

Is any thing too hard for the LORD? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son.

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;

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.

And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground,

And the LORD said, Because the cry of Sodom and Gomorrah is great, and because their sin is very grievous;

I will go down now, and see whether they have done altogether according to the cry of it, which is come unto me; and if not, I will know.

And Abraham drew near, and said, Wilt thou also destroy the righteous with the wicked?

That be far from thee to do after this manner, to slay the righteous with the wicked: and that the righteous should be as the wicked, that be far from thee: Shall not the Judge of all the earth do right?

And the LORD said, If I find in Sodom fifty righteous within the city, then I will spare all the place for their sakes.