"I will maintain My covenant between Me and you, and your offspring to come, as an everlasting covenant throughout the ages, to be God to you and to your offspring to come. I assign the land you sojourn in to you and your offspring to come, all the land of Canaan, as an everlasting holding. I will be their God."
God further said to Abraham, "As for you, you and your offspring to come throughout the ages shall keep My covenant. Such shall be the covenant between Me and you and your offspring to follow which you shall keep: every male among you shall be circumcised.
"You shall circumcise the flesh of your foreskin, and that shall be the sign of the covenant between Me and you. And throughout the generations, every male among you shall be circumcised at the age of eight days. As for the homeborn slave and the one bought from an outsider who is not of your offspring, they must be circumcised, homeborn, and purchased alike. Thus shall My covenant be marked in your flesh as an everlasting pact. And if any male who is uncircumcised fails to circumcise the flesh of his foreskin, that person shall be cut off from his kin; he has broken My covenant."
And God said to Abraham, "As for your wife Sarai, you shall not call her Sarai, but her name shall be Sarah. I will bless her; indeed, I will give you a son by her. I will bless her so that she shall give rise to nations; rulers of peoples shall issue from her." Abraham threw himself on his face and laughed, as he said to himself, "Can a child be born to a man a hundred years old, or can Sarah bear a child at ninety?" And Abraham said to God, "O that Ishmael might live by Your favor!" God said, "Nevertheless, Sarah your wife shall bear you a son, and you shall name him Isaac; and I will maintain My covenant with him as an everlasting covenant for his offspring to come. As for Ishmael, I have heeded you. I hereby bless him. I will make him fertile and exceedingly numerous. He shall be the father of twelve chieftains, and I will make of him a great nation. But My covenant I will maintain with Isaac, whom Sarah shall bear to you at this season next year." And when He was done speaking with him, God was gone from Abraham.
Then Abraham took his son Ishmael, and all his homeborn slaves and all those he had bought, every male in Abraham’s household, and he circumcised the flesh of their foreskins on that very day, as God had spoken to him. Abraham was ninety-nine years old when he circumcised the flesh of his foreskin, and his son Ishmael was thirteen years old when he was circumcised in the flesh of his foreskin. Thus Abraham and his son Ishmael were circumcised on that very day; and all his household, his homeborn slaves and those that had been bought from outsiders, were circumcised with him.