Genesis 17:10

7 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 to thee and to thy seed after thee.

8 And I will give to thee, and to thy seed after thee, the land in which thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God.

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

10 This [is] my covenant, which ye shall keep between me and you, and thy seed after thee; Every male-child among you shall be circumcised.

11 And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you.

12 And he that is eight days old shall be circumcised among you, every male-child in your generations, he that is born in the house, or bought with money of any stranger, who [is] not of thy seed.

13 He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant.