Marcion was a second century heretic. He taught that the God of the Old Testament was a separate and lower entity than the God of the New Testament. He rejected the entire Old Testament, and compiled his own canon of the New Testament, selecting only those sections which agreed with his theology. Unfortunately, we see this happening today! There are modern preachers suggesting that the believer should not read the Old Testament, that the teachings of Jesus were only for those under the law and other passages of the New Testament are no longer relevant.