Robert Millet notes that in the eighth chapter of Helaman, we have Nephi testifying to the people and especially to the corrupt judges of "the coming of the Messiah," who would be "lifted up" (or atone for the sins of mankind) that "as many as should look upon the Son of God with faith, having a contrite spirit" (covenant people), "might live, even unto that life which is eternal" (Helaman 8:13-15). How did Nephi testify? He drew upon the old prophets, had them testify, and then bore his own witness.
yea, did [Moses] not bear record that the Son of God should come? And as he lifted up the brazen serpent in the wilderness, even so shall he be lifted up who should come. And as many as should look upon that serpent should live, even so as many as should look upon the Son of God with faith, having a contrite spirit, might live, even unto that life which is eternal. (Helaman 8:14-15)
Now by referring to the footnotes, the reader will find that this prophecy of Moses concerning the serpent is recorded in Alma 33:19-22, and is also referred to in 2 Nephi 25:20 and Numbers 21:6-9. But what is fascinating is what comes next:
And now behold, Moses did not only testify of these things, but also all the holy prophets, from his days even to the days of Abraham. Yea, and behold, Abraham saw of his coming, and was filled with gladness and did rejoice. (Helaman 8:16-17; emphasis added)
Millet asks, Now where can you go in the Old Testament to find an occasion where Abraham saw the coming of the Son of Man and rejoiced? I would recommend that you would have difficulty in finding that. It is not there. But in the New Testament, notice. As one reads in the eighth chapter of John, they find that Christ confronted the Pharisees on what it meant to be covenant children of God (or children of Abraham--Abraham's seed). Jesus told them "if ye were Abraham's children, ye would do the works of Abraham" (v. 39). As the discussion progressed, Jesus proclaimed his role as Redeemer of Israel (or Redeemer of "Abraham's seed") by saying: "Verily, verily, I say unto you, If a man keep my saying, he shall never see death.
To this the Jews responded, "Abraham is dead, and the prophets; and thou sayest, If a man keep my saying he shall never taste of death. Art thou greater than our father Abraham, which is dead? and the prophets are dead: whom makest thou thyself?"
To this Jesus responded once again, quoting scripture in order to teach about his atoning and redeeming role in the salvation of God's covenant children, "Your father Abraham rejoiced to see my day: and he saw it, and was glad."
But once again the Jews misunderstood and said: "Thou art not yet fifty years old, and hast thou seen Abraham?" (Of course, that's not what Jesus said. He said, "Abraham saw me.")
In a final attempt to set the scriptural record straight, Jesus said unto them, "Verily, verily, I say unto you, Before Abraham was, I AM [Jehovah].
So what's going on here? Where is Jesus quoting from in his argument concerning covenant children, eternal life, and His redeeming role when he said, "Your father Abraham rejoiced to see my day: and he saw it, and was glad."? There is no scriptural passage in the Old Testament which corresponds to his words. But we certainly find it in the Book of Mormon, here in the eighth chapter of Helaman, where Nephi apparently quotes from the brass plates. Let me add some detail about these brass plates, and I like the way Elder Bruce R. McConkie said this in 1984 in an address given at BYU:
From various Book of Mormon references we gain a glimpse of what is on the brass plates. They contain the record of the Jews down to the days of Zedekiah, including . . . the prophecies of the holy prophets . . . They contain, in their perfect form, the law of Moses and the five books of Moses . . . They contain the writings of Joseph . . . [of] which few have been greater. They contain books of holy scripture of which the world does not dream, including the writings of Zenock, Neum, and Zenos. But what interests us more than the books included on the brass plates is the tone and tenor and general approach to the gospel and to salvation that they set forth. They are gospel oriented and speak of Christ and the various Christian concepts which the world falsely assumes to have originated with Jesus and the early apostles. (Bruce R. McConkie, "The Doctrinal Restoration," in The Joseph Smith Translation, the Restoration of Plain and Precious Things, ed. Monte Nyman and Robert L. Millet, Provo, 1985, 17.)
Remember, that one of the major purposes of the Book of Mormon was to establish the essential truthfulness of the Bible (see 1 Nephi 13:40). For many years, you know, we have approached this in the wrong direction. We have gone out trying to prove the Book of Mormon from the Bible. The Lord never intended that. The Lord's purpose is that he knew there would come a time when the Bible itself would be in question. So he raises up a prophet, restores to him ancient records, gives him power to translate them, and they come forth and help establish essential truthfulness. That is why the Lord would say, in the 20th section of the Doctrine and Covenants, that the Book of Mormon is given for the purpose of proving to the world that the holy scriptures are true.
Now let me read something out of the Joseph Smith Translation. But before I do let me say that I am convinced, after years of study, that the closest approximation you and I have to the brass plates, that is, one of the best ways we can get close to understanding what was on the brass plates, is Joseph Smith's translation of the Bible. If you want to know what was there beyond what is obviously in the Book of Mormon, look at the Joseph Smith Translation. Now in JST Genesis 15:9-12, we find the following:
And Abram said, Lord God, how wilt thou give me this land for an everlasting inheritance? And the Lord said, Though thou was dead, yet am I not able to give it thee? And if thou shalt die, yet thou shalt possess it, for the day cometh, that the Son of Man shall live; but how can he live if he be not dead? He must first be quickened.
What did Abraham understand? The everlasting covenant promise of eternal life. Now listen to this:
And it came to pass, that Abram looked forth and saw the days of the Son of Man, and was glad, and his soul found rest, and he believed in the Lord; and the Lord counted it unto him for righteousness.
[Adapted from Robert L. Millet, "The Prophets of the Brass Plates," Video Transcript, FARMS, 1996, pp. 17-18, 3-4, 7-8] [See the commentary on 1 Nephi 13:40; Alma 33:11]