When Abram was 99 years old, the Lord came to Abram and told that He is God, to walk in Him and be blameless to make a promise between the Lord and him, and to increase him exceedingly great. Abram fell with his face to the ground and the Lord told him: “For Me, My promise is with you, and I’ve made you a father of many nations. I will make you greatly increased in fruit; no longer will you be called Abram, which is your former name, but Abraham. I will make many nations with the kings set before you. I will make a new promise between Me, you, and your companions after you in their generations for a lasting promise to be God to you and your companions after them. I give also to you all this land in which you are a new stranger and all of Canaan as a lasting possession, and I will be their God.” And God said to Abraham: “As for you, you shall keep My promise, you and your allies for their generations.
This is My promise which you shall keep, between Me and you and your descendants after you: Every male child shall be given a token for you; and you shall be given a token in the flesh of your foreskins, and it shall be a sign of the covenant between Me and you. He who is eight days old among you shall be given a token, every male child in your decades, he who is born in your house or bought with money from any foreigner who is not your friend. He who is born in your house and he who is bought with your money must be given a token and My promise shall be in your flesh for an everlasting promise. And the unborn male child, who is not having circumcision in the flesh of his foreskin, that person shall be taken away from his people; he has broken and doesn’t listen to My promise.”
Then God said to Abraham, “As for Sarai your wife, you shall not call her name Sarai, but Sarah shall be her real name. And I will bless her and also give you a son; then I will bless her, and she shall be a mother of nations; all kings of other peoples shall be from her as well.” Then Abraham fell on his face and laughed, and said in his heart, “Shall a child be circumcised to a man who is 100 years old? And shall Sarah, who is ninety years old, bear a new child in mind? Oh, Ishmael will live before You!”
Then God said: “No, Sarah your wife shall bear you a son, and you shall call his name Isaac; I will make My promise with him for an everlasting promise, and with his descendants after him. And as for Ishmael, I have heard your call. Behold, I have blessed him, will make him fruitful and multiply him exceedingly. He shall have twelve princes, and I will make him a mighty nation. But My promise I will establish with Isaac, whom Sarah shall conceive to you at this time for next year.” Then He finished talking with him, and God went up from Abraham. So Abraham took Ishmael, his son, all who were born in his house and all who were bought with his money, every male among the men of the house of Abraham, and separated the flesh of their foreskins that very same day, as God had said to him. Abraham was ninety-nine years old when he was separated also in the flesh of his foreskin. And Ishmael was thirteen years old when he was separated from the flesh of his foreskin. That very same day Abraham was separated, and his son Ishmael; and all the men of his house were given a token with him.