In the time of Moses the children of Israel were stiffnecked and hard of heart. As a result, they lost the privilege of living the fulness of the higher law. Instead, along with portions of the higher law that they were still allowed to live, the law of Moses (the lesser law) was added to help them come to Christ. In Doctrine and Covenants Section 84 we read:
18 And the Lord confirmed a priesthood also upon Aaron and his seed, throughout all their generations, which priesthood also continueth and abideth forever with the priesthood which is after the holiest order of God.19 And this greater priesthood administereth the gospel and holdeth the key of the mysteries of the kingdom, even the key of the knowledge of God.21 And without the ordinances thereof, and the authority of the priesthood, the power of godliness is not manifest unto men in the flesh;22 For without this no man can see the face of God, even the Father, and live.23 Now this Moses plainly taught to the children of Israel in the wilderness, and sought diligently to sanctify his people that they might behold the face of God;24 But they hardened their hearts and could not endure his presence; therefore, the Lord in his wrath, for his anger was kindled against them, swore that they should not enter into his rest while in the wilderness, which rest is the fulness of his glory.26 And the lesser priesthood continued, which priesthood holdeth the key of the ministering of angels and the preparatory gospel;
Notice the difference between the unbelieving Jews and the teachable Nephites.
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 over a thousand years. The Nephites possessed written records of the law on the brass plates, and Nephite prophets taught and observed the law. Earlier Book of Mormon prophets taught that the law of Moses would eventually be fulfilled. Nephi, Jacob, and Abinadi all prepared their people to eventually accept the ending of the law of Moses. Elder Jeffrey R. Holland of the Quorum of the Twelve Apostles identified the reasons the Nephites were able to give up the old law and embrace the new:
“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.] 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]
“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” (Christ and the New Covenant , 156–57).
When the resurrected Savior visited the Nephites, He taught them that the law had been completely fulfilled in Him. Elder Bruce R. McConkie stated: “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.” (Doctrinal New Testament Commentary, 1:219–20; see also Stephen E. Robinson, “The Law after Christ,” Ensign, Sept. 1983, 68–73).
Jesus Christ taught the Nephites that not only were they to avoid murder and adultery, but also anger and lust—conditions of the heart that lead to murder and adultery. 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.Take a moment and compare the words of Christ given in Third Nephi to the Beatitudes found in the New Testament.You will notice subtle changes in the verse that make all the difference. I hope we are able to accept in our own lives this higher law, and offer unto the Lord our broken hearts and contrite spirits.
The ritual aspects of the law of Moses included commandments about animal sacrifice and burnt offerings—what Abinadi called “performances” and “ordinances". 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. 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, and the ordinances were fulfilled in the sense that it concluded. 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.