The Decalogue (Divine Positive Law) is an explicit statement of what the Natural Law requires of us. Hence, it covers not only Catholics or Christians, but all men. Jesus Christ confirms the commands of the Old Law but reveals more demands for His followers.
“…while being holy, spiritual, and good, the Old Law was still imperfect because in itself it did not give the strength and the grace of the Spirit for its observance.” Man had to wait for the Messiah who would hand down a law that included “the strength and the grace of the Spirit” as part of the “package.”