“Clearly the Nephite congregation understood this more readily than did the Jewish world, partly because the Nephite prophets had been so careful to teach the transitional nature of the law. Abinadi had said, ‘It is expedient that ye should keep the law of Moses as yet; but I say unto you, that the time shall come when it shall no more be expedient to keep the law of Moses’ [Mosiah 13:27; italics added]. In that same spirit Nephi emphasized, ‘We speak concerning the law that our children may know the deadness of the law; and they, by knowing the deadness of the law, may look forward unto that life which is in Christ, and know for what end the law was given. And after the law is fulfilled in Christ, that they need not harden their hearts against him when the law ought to be done away’ [2 Nephi 25:27; italics added].
“That kind of teaching—a caution against hardening one’s heart against Christ in ignorant defense of the law of Moses—could have served (and saved) so many living in the Old World then and living throughout the world now” (Jeffrey R. Holland, Christ and the New Covenant: The Messianic Message of the Book of Mormon [1997], 156–57).
By the time of the Savior’s mortal ministry, the law of Moses had been at the foundation of Israelite religious and social life for more than a thousand years. The Nephites possessed written records of the law on the brass plates, and Nephite prophets taught and observed the law. When the Savior visited the Nephites, He taught them that the law had been completely fulfilled in Him. However, they were not to think of the law of Moses as having been destroyed or having “passed away” (3 Nephi 12:17–18). How is it that the Savior “fulfilled” but did not “destroy” the law of Moses? The law of Moses included both moral and ritual aspects.
The moral aspects included such commandments as “Thou shalt not kill” and “Thou shalt not commit adultery.” Jesus Christ taught the Nephites that they were to avoid not only murder and adultery, but also anger and lust—conditions of the heart that lead to murder and adultery (see 3 Nephi 12:21–30). Thus the gospel of Jesus Christ fulfilled the law in the sense that it expanded the moral aspects of the law of Moses by being a higher law; it included the moral imperatives of the law of Moses and placed them in the context of broader gospel principles that require a change of heart.
The ritual aspects of the law of Moses included commandments about animal sacrifice and burnt offerings—what Abinadi called “performances” and “ordinances” (Mosiah 13:30). The Nephite prophets understood that these parts of the law of Moses were meant to help people look forward to the atoning sacrifice of Jesus Christ (see 2 Nephi 25:24; Jacob 4:5; Mosiah 16:14–15). Therefore, when the Savior’s mortal mission was completed, these forward-looking ordinances could no longer look ahead to a future event—the event had happened. Thus the Savior taught the Nephites that animal sacrifices and burnt offerings were to be “done away” and that His followers were to offer instead the “sacrifice” of “a broken heart and a contrite spirit” (3 Nephi 9:19–20). In place of ordinances that looked forward to the Atonement, the Savior instituted the sacrament, an ordinance of remembrance, to look back to the Savior’s atoning sacrifice (see 3 Nephi 18:1–11).
“Jesus came to restore that gospel fulness which men had enjoyed before the day of Moses, before the time of the lesser order. Obviously he did not come to destroy what he himself had revealed to Moses anymore than a college professor destroys arithmetic by revealing the principles of integral calculus to his students. Jesus came to build on the foundation Moses laid. By restoring the fulness of the gospel he fulfilled the need for adherence to the terms and conditions of the preparatory gospel. No one any longer needed to walk by the light of the moon, for the sun had risen in all its splendor” (Bruce R. McConkie, Doctrinal New Testament Commentary [1965], 1:219–20; see also Stephen E. Robinson, “The Law after Christ,” Ensign, Sept. 1983, 69–73).
What did Jesus mean when He said, “The covenant which I have made with my people is not all fulfilled” (3 Nephi 15:8)? Jehovah made a covenant with Abraham anciently. Abraham was promised (1) eternal posterity, (2) a land of inheritance, and (3) God’s priesthood power. These promises were also made to Abraham’s descendants (see D&C 132:30–31) and will be fulfilled in the future.