It's a familiar refrain; "out of the mouths of two or three witnesses." And who would object? One witness can easily be challenged. Two witnesses (especially independent ones) provide more credibility. And, in my opinion, each additional witness increases credibility exponentially. Knowing and remembering that the Lord uses the law of witnesses as a modus operandi for establishing His word can be especially helpful as we study the scriptures - particularly the Book of Mormon. It seems to me that no other canon is so surrounded by witnesses. They are like sentinels at the gate of truth for "the most correct book on earth." Let's look at a few of these, starting with some that my favorite apostle, Jeffrey R. Holland, gives us in Christ and The New Covenant:
In keeping with this same covenantal principle, it is interesting to note that there were three earlier witnesses—special witnesses—not only of the divine origins of the Book of Mormon but also of Divinity himself. These early witnesses were Nephi, Jacob, and Isaiah, and it is not by coincidence that their testimonies appear so conspicuously at the beginning of this ancient record . . .
. . . What is known is that most of the "greater views" of the gospel found in the teachings of the small plates of Nephi come from the personal declarations of these three great prophetic witnesses of the premortal Jesus Christ—Nephi, Jacob, and Isaiah. These three doctrinal and visionary voices make clear at the very outset of the Book of Mormon why it is "another testament of Jesus Christ."
In declaring the special preparation these three had for receiving and teaching such "greater views" of the gospel, Nephi revealed the most persuasive qualification of all: They had seen the premortal Jesus Christ.
And now I, Nephi, write more of the words of Isaiah, for my soul delighteth in his words. For I will liken his words unto my people, and I will send them forth unto all my children, for he verily saw my Redeemer, even as I have seen him.
And my brother, Jacob, also has seen him . . . ; wherefore, I will send their words forth unto my children to prove unto them that my words are true. Wherefore, by the words of three, God has said, I will establish my word.
Nephi concluded, "My soul [and he could have said the souls of all three] delighteth in proving unto [our] people the truth of the coming of Christ, . . . that save Christ should come all men must perish."
One could argue convincingly that the primary purpose for recording, preserving, and then translating the small plates of Nephi was to bring forth to the dispensation of the fulness of times the testimony of these three witnesses. Their writings constitute a full 135 of the 145 pages from the small plates. By the time one has read Nephi, Jacob, and Isaiah in these first pages, a strong foundation has been laid for what Nephi called "the doctrine of Christ." It is a foundation conforming perfectly to the title page of the Book of Mormon. After reading these three witnesses from the small plates of Nephi, the reader knows two things in bold relief: that Jesus is the Christ, the Son of the Living God, and that God will keep his covenants and promises with the remnants of the house of Israel. Those two themes constitute the two principal purposes of the Book of Mormon, and they are precisely the introductory themes addressed by Nephi, Jacob, and Isaiah.
And in addition to providing a witness of Christ, these three witnesses fall into another pattern set by the Lord time and time again; that of a type and shadow. These three witnesses of Christ and of the divinity of the Book of Mormon have, by virtue of their testimonies, lent weight to Joseph Smith and the procedure he followed of choosing three special witnesses (Martin Harris, Oliver Cowdery and David Whitmer). These three men experienced a combination of physical (touching and turning the plates) and supernatural (angelic visitation) manifestations that could, with validity, put to rest any claim that they were victims of an elaborate hoax. They would railroad detractors into the unenviable position of combating the gravity of fervent eyewitness testimonies. Joseph Smith was not alone.
The Book of Mormon is surrounded by men who boldly stood to say "We have seen these things." These include Jacob, Nephi, Isaiah, Martin, David, Oliver, Joseph and the testimonies of the additional eight witnesses.
Why is this all so important? We know that we can ultimately know the truth of all things by the power of the Holy Ghost right? So why would/does the Lord bother to use such an archaic method to establish His word? Holy Ghost vs. farmers and nomads seems akin to using an abacus to prove an equation instead of using a graphing calculator.
Sadly, it's because all we understand is the abacus. How glorious it would be if all people were so spiritually inclined that when a missionary eventually arrived with the gospel in his hands, the Holy Ghost could immediately "witness" to the truth of the message. Wouldn't it be nice if we, as members, could be converted to each of the lessons that come from General Conference the first time? Instead, we have to hear at least three apostles reinforce the message of the dangers of Internet pornography, et.al. before we start to get the hint!
Until then, we can certainly be grateful for the law of witnesses. We can thank the authors of the Book of Mormon and others for helping us understand the great lengths to which the Lord will go to bring us back to Him. Even if it means breaking out His dusty old abacus and teaching us slide by slide, witness by witness.