3 Nephi 12:4 - 20

4 And again, blessed are all they that mourn, for they shall be comforted.
5 And blessed are the meek, for they shall inherit the earth.
6 And blessed are all they who do hunger and thirst after righteousness, for they shall be filled with the Holy Ghost.
7 And blessed are the merciful, for they shall obtain mercy.
8 And blessed are all the pure in heart, for they shall see God.
9 And blessed are all the peacemakers, for they shall be called the children of God.
10 And blessed are all they who are persecuted for my name's sake, for theirs is the kingdom of heaven.
11 And blessed are ye when men shall revile you and persecute, and shall say all manner of evil against you falsely, for my sake;
12 For ye shall have great joy and be exceedingly glad, for great shall be your reward in heaven; for so persecuted they the prophets who were before you.

(Book of Mormon | 3 Nephi 12:4 - 12)

My comments:
The Lord delivers the Beatitudes. Great blessings are promised to the humble followers of Christ. They will be compassionate, meek, gospel studiers, merciful, pure in heart, peacemakers, and they will bare with patience the afflictions that others throw on them for their belief in Christ.
The Kingdom of Heaven will be filled with those that possess these qualities.

13 Verily, verily, I say unto you, I give unto you to be the salt of the earth; but if the salt shall lose its savor wherewith shall the earth be salted? The salt shall be thenceforth good for nothing, but to be cast out and to be trodden under foot of men.
14 Verily, verily, I say unto you, I give unto you to be the light of this people. A city that is set on a hill cannot be hid.
15 Behold, do men light a candle and put it under a bushel? Nay, but on a candlestick, and it giveth light to all that are in the house;
16 Therefore let your light so shine before this people, that they may see your good works and glorify your Father who is in heaven.

(Book of Mormon | 3 Nephi 12:13 - 16)

My comments:
The followers of Christ are to be the salt of the earth. Salt was used as a food preservative in the ancient world; it was considered essential for life. The Savior continues this line of thinking as he states that we are the light of the world.
Light chases away darkness. It gives clarity and meaning to things that could not otherwise be understood. As we let our light shine through our example and good works, others will see that light, and be drawn to our Father in Heaven.

17 Think not that I am come to destroy the law or the prophets. I am not come to destroy but to fulfil;
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.

(Book of Mormon | 3 Nephi 12:17 - 20)

My comments:
Jesus Christ fulfilled the law of Moses. The law was intended to bring people to Christ. Now that he had come and offered Himself as a sinless sacrifice, the law of Moses was no longer relevant. In place of the law, He now requires a broken heart and a contrite spirit.
We are saved as we come unto Christ and keep His commandments.