Adam Clarke on Genesis 17:7

An everlasting covenant - ברית עולם berith olam. See note on Gen 13:15. Here the word olam is taken in its own proper meaning, as the words immediately following prove - to be a God unto thee, and thy seed after thee; for as the soul is to endure for ever, so it shall eternally stand in need of the supporting power and energy of God; and as the reign of the Gospel dispensation shall be as long as sun and moon endure, and its consequences eternal, so must the covenant be on which these are founded.