I was supposed to teach this lesson and started preparing for it, but then we decided to go out of town. This is also why I am late in posting, please excuse me. When I called someone to substitute I was a little sad because I didn't study this reading in detail as I would have liked. But then these four chapters contain so much, that I could study them for a very, very long time. I did read a little of John W. Welch's book, "The Sermon at the Temple and the Sermon on the Mount," (the whole text is at this link) and was overwhelmed by the amount comparison and information. Basically, Brother Welch believes that the sermon that was given to the Nephites by the Savior was in preparation for them to receive temple covenants. Indeed they are. Though the words given by the Savior would benefit anyone who is seeking to live a better life.
There are differences in the text of the Sermon on the Mount compared to the text given to the Nephites. He gives the same basic beattitudes, but must give a little more because the people are now under a new law and in fact, a new church, since Christ's atonement and resurrection fulfills the law of Moses. The Savior now asks the people, and us, to live a higher law, as He explains in 3 Nephi 12:17-20 (italics added):
17 Think not that I am come to destroy the law or the prophets. I am not come to destroy but to fulfil;In my last post I talked about the introduction of continuing revelation and these chapters continue with that thought. In verse 20, Christ specifically mentions following the commandments He gives "at this time," meaning, that whatever He tells them now supersedes what He gave in the Old Testament. Or rather, he adds to the doctrine and takes away the necessity of offering sacrifices upon an altar. He continues on, giving examples of what He, through the prophets, commanded, but then gives a higher law, the rest of chapter 12 and 13-15.
18 For verily I say unto you, one jot nor one tittle hath not passed away from the law, but in me it hath all been fulfilled.
19 And behold, I have given you the law and the commandments of my Father, that ye shall believe in me, and that ye shall repent of your sins, and come unto me with a broken heart and a contrite spirit. Behold, ye have the commandments before you, and the law is fulfilled.
20 Therefore come unto me and be ye saved; for verily I say unto you, that except ye shall keep my commandments, which I have commanded you at this time, ye shall in no case enter into the kingdom of heaven.
If you have not read these chapters yourself, I highly recommend it. I don't think I will even try to pick out something to discuss, other than to say that the fulfillment of the law and the request to live the law of Christ, is a more obvious call to "come unto the Holy One of Israel." It is not symbolic, it is not a representative sacrifice that helps us remember Him, following his commandments are not just laws to abide by and live a relatively happy life. He is telling us that obeying and living His commandment will actually bring us to Him, literally. He has now lived in this world and has become our example of how to live in this world. We can rest assured that the Savior's example is the perfect one and one that has not existed before in the world at the time of his appearance to the Nephites. At His visit, he was perfected, even as his Father, God, is perfect (see 12:48). Our choice to live commandments and laws and behave in certain ways is not symbolic, it is real. We can come directly to Him. He asks us to (12:20): "come unto me and be ye saved."