GAL 3:21

21 [If someone should ask, “When God gave his] laws [to Moses] long [after he told Abraham] what he was promising [to give to him, was he] changing his mind?” [I would reply that God] certainly did not [change his mind when he did that]! If God had given a law that could enable people to live [eternally], then it actually would be because of people [obeying that] law that God would erase the record of their sins.