The gospel is structured to help us progress to ever higher levels of spirituality in ever more perfect compliance with the patterns of heaven. The law of Moses had been a schoolmaster intended to help the people look forward to Christ, as Elder Jeffrey R. Holland explains:
Thus it is crucial to understand that the law of Moses was overlaid upon, and thereby included, many basic parts of the gospel of Jesus Christ, which had existed before it. It was never intended to be something apart or separated from, and certainly not something antagonistic to, the gospel of Jesus Christ. It was more elementary than the full gospel—thus its schoolmaster’s role in bringing people to the gospel—but its purpose was never to have been different from the higher law. Both were to bring people to Christ. (Christ and the New Covenant: The Messianic Message of the Book of Mormon [Salt Lake City: Deseret Book, 1997], 147)
The Lord is the one who has implemented the law of Moses, and now it is He who proceeds to give the higher law. The Lord has already announced to the people during the three-day period of profound darkness a new and illuminating doctrine: “And ye shall offer up unto me no more the shedding of blood; yea, your sacrifices and your burnt offerings shall be done away, for I will accept none of your sacrifices and your burnt offerings. And ye shall offer for a sacrifice unto me a broken heart and a contrite spirit. And whoso cometh unto me with a broken heart and a contrite spirit, him will I baptize with fire and with the Holy Ghost” (3 Nephi 9:19–20). Now, continuing His sermon at the temple in Bountiful, the Lord expounds on this remarkable new form of sacrifice by unfolding to the people the extraordinary transition from the old patterns of external ordinances under the law of Moses to the new patterns of devotion and spirituality characteristic of the higher law. He makes clear that the law of Moses is fulfilled in Him. Commenting on this principle, Elder Bruce R. McConkie declares:
When he spoke on the Mount of Beatitudes, the law was not yet fulfilled; now that he had eaten the Last Supper and introduced the sacrament; now that he had suffered in the garden and on the cross; now that he had come forth in immortality—the law was fulfilled. It would appear, however, that many among the Nephites, during these transitional months, had not fully envisioned that the lesser law of Moses had been supplanted by the higher law of Christ. And so now Jesus “perceived that there were some among them who marveled, and wondered what he would concerning the law of Moses; for they understood not the saying that old things had passed away, and that all things had become new.” (The Mortal Messiah: From Bethlehem to Calvary, 4 vols. [Salt Lake City: Deseret Book, 1979–1981], 4:309)