What did God tell Abraham?
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.
9And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations.
4And said unto me, Behold, I will make thee fruitful, and multiply thee, and I will make of thee a multitude of people; and will give this land to thy seed after thee for an everlasting possession.
Does anyone want to argue with God about the word everlasting?
Case closed. God will STILL bring this to pass!