I will be their God— The spiritual and temporal covenant are blended together, and with propriety, as the latter was eminently typical of the former. The Scripture covenant with Abraham, and all his children by faith, is strictly everlasting; for it extends to the possession of that heavenly and better country, the celestial Canaan, where God will be the God of all faithful believers throughout eternity. See Revelation 21:3 and Jeremiah 31:33.
Related Commentaries of Genesis 17:8
Genesis 17:8
8 And 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.