Genesis 17:7-10

7And 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. 8And I will give unto thee, and to thy seed after thee, the land wherein thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God.1

9And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations. 10This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised.