4 And I command you that ye shall write these sayings after I am gone, that if it so be that my people at Jerusalem, they who have seen me and been with me in my ministry, do not ask the Father in my name, that they may receive a knowledge of you by the Holy Ghost, and also of the other tribes whom they know not of, that these sayings which ye shall write shall be kept and shall be manifested unto the Gentiles, that through the fulness of the Gentiles, the remnant of their seed, who shall be scattered forth upon the face of the earth because of their unbelief, may be brought in, or may be brought to a knowledge of me, their Redeemer.
5 And then will I gather them in from the four quarters of the earth; and then will I fulfil the covenant which the Father hath made unto all the people of the house of Israel.
6 And blessed are the Gentiles, because of their belief in me, in and of the Holy Ghost, which witnesses unto them of me and of the Father.
7 Behold, because of their belief in me, saith the Father, and because of the unbelief of you, O house of Israel, in the latter day shall the truth come unto the Gentiles, that the fulness of these things shall be made known unto them.
(Book of Mormon | 3 Nephi 16:4 - 7)
The Nephites are to keep their records, scriptures, which will be given to the Gentiles, and the Gentiles will bring them forth, and be brought to the Savior by these writings.
After these records, the Book of Mormon, has come forth, the Lord will gather in the lost tribes of Israel from the four quarters of the earth. Then will the Lord fulfill the covenant which He made to Abraham.
The Abrahamic Covenant can be found in the Pearl of Great Price, Abraham 2: 6-11:
6 But I, Abraham, and Lot, my brother's son, prayed unto the Lord, and the Lord appeared unto me, and said unto me: Arise, and take Lot with thee; for I have purposed to take thee away out of Haran, and to make of thee a minister to bear my name in a strange land which I will give unto thy seed after thee for an everlasting possession, when they hearken to my voice.
7 For I am the Lord thy God; I dwell in heaven; the earth is my footstool; I stretch my hand over the sea, and it obeys my voice; I cause the wind and the fire to be my chariot; I say to the mountains—Depart hence—and behold, they are taken away by a whirlwind, in an instant, suddenly.
8 My name is Jehovah, and I know the end from the beginning; therefore my hand shall be over thee.
9 And I will make of thee a great nation, and I will bless thee above measure, and make thy name great among all nations, and thou shalt be a blessing unto thy seed after thee, that in their hands they shall bear this ministry and Priesthood unto all nations;
10 And I will bless them through thy name; for as many as receive this Gospel shall be called after thy name, and shall be accounted thy seed, and shall rise up and bless thee, as their father;
11 And I will bless them that bless thee, and curse them that curse thee; and in thee (that is, in thy Priesthood) and in thy seed (that is, thy Priesthood), for I give unto thee a promise that this right shall continue in thee, and in thy seed after thee (that is to say, the literal seed, or the seed of the body) shall all the families of the earth be blessed, even with the blessings of the Gospel, which are the blessings of salvation, even of life eternal.
Through Abraham’s seed, which the Nephites and Lamanites are definitely a part of, all nations of the earth will be blessed. We are blessed through the scriptures, the Bible and the Book of Mormon.
These books of scripture bless all those that read and follow their teachings.