According to the record of Nephi4, after the visit of the Savior the Nephites "did not walk any more after the performances and ordinances of the law of Moses; but they did walk after the commandments which they had received from their Lord and their God . . . (4 Nephi 1:12). Some might think that this statement implies that everything taught by the Savior was new, however John Tvedtnes notes the following:
Paul wrote that the law of Moses was "added" because of transgression (Galatians 3:19). To what was it added? Was it not to the higher law of the gospel revealed through Moses? The Book of Mormon indicates that it was only this added part, the "performances and ordinances" or "statutes and judgments," that was abolished with Christ's coming (see 2 Nephi 25:30; Alma 25:15; 4 Nephi 1:12). What remained was the law that God had always revealed to his prophets even before Moses' time.
[John Tvedtnes, Book Review in Review of Books on the Book of Mormon, Vol. 4 1992, p. 230]