Note: This is a comment I made on my last post, but I thought it was pertinent enough to make it into a post of itself.
The concept of “keys” is not absent from the Book of Mormon. Whenever God has chosen to give authority to man to perform ordinances in His name, it has been by ordination and a dispensation of keys.
Taking the example of Alma, where did he get his authority? President Joseph Fielding Smith said this:
We should take into consideration in the study of the Book of Mormon the fact that it is an abridgment taken from the records or history that had been kept by the prophets among the Nephites. Therefore, many of the details are lacking. This is equally true of the history of Israel as it has come down through the years to us in the Bible. We are left to accept the fact that Lehi, when he left Jerusalem, held divine authority and that this divine power was handed down from generation to generation until the time of the visitation of the Savior. Moreover, while the detail is lacking, the evidence is very clear that the Melchizedek Priesthood was possessed by the Nephites.
There were none of the tribe of Levi among them, therefore it was by virtue of the Melchizedek Priesthood that they officiated. There are many passages in the Book of Mormon in which reference is given to the Holy Priesthood. We should also remember that the record that we have received is an abridgment, and therefore many of the details are of necessity missing. Moreover, we are informed that many important things have been withheld from us because of the hardness of our hearts and our unwillingness, as members of the Church, to abide in the covenants or seek for divine knowledge.
In the case of Alma and his priesthood, we are left to surmise that he legally and divinely received it before the days of King Noah. We read that Zeniff, the father of Noah, was a righteous man. Alma evidently received the priesthood in the days of Zeniff, and at no time did he fully accept the teachings nor with full purpose follow the counsels and procedure of Noah and his wicked priests…
Just at what time Alma received the priesthood is not clearly stated, but we may presume that it occurred before Noah came to the throne. Moreover, we must also conclude that Alma at no time truly entered into the wickedness of this wicked king…
Where did Alma get his authority? Evidently he obtained it when he received the priesthood, which through his repentance he had not lost. There can be no serious question in relation to his authority, for it is written – “And it came to pass that Alma; having authority from God, ordained priests; even one priest to every fifty of their number did he ordain to preach unto them, and to teach them concerning the things pertaining to the kingdom of God” (Mosiah 18:18). (Joseph Fielding Smith, Answers to Gospel Questions, vol. 4, 161-162.)
Whenever anyone is ordained to the priesthood, there is a conferral of keys. One does not hold the priesthood without a priesthood office. Every office holds keys of authority, or else there is no priesthood. Whenever Alma received his authority, it was by ordination from an authorized servant of God, and it contained keys.
Consider these scriptures that contain the concept of keys of authority being used and conferred:
Behold, thou art Nephi, and I am God. Behold, I declare it unto thee in the presence of mine angels, that ye shall have power over this people, and shall smite the earth with famine, and with pestilence, and destruction, according to the wickedness of this people.
Behold, I give unto you power, that whatsoever ye shall seal on earth shall be sealed in heaven; and whatsoever ye shall loose on earth shall be loosed in heaven; and thus shall ye have power among this people. (Hel. 10:6–7)
And it came to pass that I, Nephi, did consecrate Jacob and Joseph, that they should be priests and teachers over the land of my people. (2 Nephi 5:26)
And Ammon said that a seer is a revelator and a prophet also; and a gift which is greater can no man have, except he should possess the power of God, which no man can; yet a man may have great power given him from God. (Mosiah 8:16)
And it came to pass that king Limhi and many of his people were desirous to be baptized; but there was none in the land that had authority from God. And Ammon declined doing this thing, considering himself an unworthy servant. (Mosiah 21:33)
And it came to pass that none received authority to preach or to teach except it were by him from God. Therefore he consecrated all their priests and all their teachers; and none were consecrated except they were just men. (Mosiah 23:17)
I, Alma, having been consecrated by my father, Alma, to be a high priest over the church of God, he having power and authority from God to do these things, behold, I say unto you that he began to establish a church in the land which was in the borders of Nephi; yea, the land which was called the land of Mormon; yea, and he did baptize his brethren in the waters of Mormon. (Alma 5:3)
And again, my brethren, I would cite your minds forward to the time when the Lord God gave these commandments unto his children; and I would that ye should remember that the Lord God ordained priests, after his holy order, which was after the order of his Son, to teach these things unto the people. (Alma 13:1)
But this is not all; they had given themselves to much prayer, and fasting; therefore they had the spirit of prophecy, and the spirit of revelation, and when they taught, they taught with power and authority of God. (Alma 17:3)
Verily I say unto you, that whoso repenteth of his sins through your words, and desireth to be baptized in my name, on this wise shall ye baptize them—Behold, ye shall go down and stand in the water, and in my name shall ye baptize them.
And now behold, these are the words which ye shall say, calling them by name, saying:
Having authority given me of Jesus Christ, I baptize you in the name of the Father, and of the Son, and of the Holy Ghost. Amen. (3 Nephi 11:23–25)
And it came to pass that when Jesus had spoken these words unto Nephi, and to those who had been called, (now the number of them who had been called, and received power and authority to baptize, was twelve) and behold, he stretched forth his hand unto the multitude, and cried unto them, saying: Blessed are ye if ye shall give heed unto the words of these twelve whom I have chosen from among you to minister unto you, and to be your servants; and unto them I have given power that they may baptize you with water; and after that ye are baptized with water, behold, I will baptize you with fire and with the Holy Ghost; therefore blessed are ye if ye shall believe in me and be baptized, after that ye have seen me and know that I am. (3 Nephi 12:1)
Just because the Book of Mormon does not mention “keys” by name does not mean that they weren’t in use extensively, and being conferred from generation to generation, throughout Book of Mormon history, because, as we can see here, they were.
On the same note, we can surmise that there is also extensive temple work and temple references in the Book of Mormon, even if superficially the temple seems to be little spoken of, but only if we are willing to look for them. Over the last several months I have found the Book of Mormon quite literally saturated with the temple, but it is because I’ve had it as a conscious focus of mine as I have been reading and studying it.