Before 1981, the Book of Mormon was simply the Book of Mormon; since then, however, it has borne the subtitle “Another Testament of Jesus Christ.” I suspect that this addition had several purposes. First almost certainly was to draw attention to Christ in a church that many consider non-Christian. (Ironically, the Book of Mormon in its doctrine cleaves pretty close to the New Testament, exhibiting few or none of the distinctive Mormon beliefs, such as temple worship or polygamy, that people see as typically Mormon heresies.) Second would be to clarify the relationship of the book to the Bible’s Old and New Testaments: not a replacement, but An Other Testament.
Growing up, I always liked the latter reason. Not only did it represent a sort of continuity as to the purpose and similarity of scripture, but I always read “testament” as if it said “testimony,” which in Mormonsprach is a declaration of faith in Jesus Christ or some aspect of His Gospel. It was nice: just as I or any other Mormon might go up before the congregation and testify to Christ’s atoning power, the prophets in the scripture hundreds of years ago were doing the same thing. This, I believe, is how most Mormons read the Book of Mormon subtitle and the subdivisions of the Christian Bible: the Old Testimony, the New Testimony, and the Other Testimony.
However, as I became better versed in the Bible (and especially non-KJV and non-English versions), I began to notice something: “testament” is not equivalent to “testimony.” In fact, when it appears in the NIV’s relation of the Last Supper (KJV: “this is my blood of the new testament”) it is translated as “covenant” and the Spanish Reina-Valera does it similarly with “pacto.” Some Protestant denominations, breaking free of traditional scriptural nomenclature, even call the Biblical subdivisions the “New Covenant” and the “Old Covenant”!
Not only revising my understanding of the scriptural basis for these names, it also keyed me into why some non-Mormon Christians might even be disturbed, not comforted, by the Book of Mormon’s subtitle’s invocation of Christ. The contexts from which the terminology arises –particularly in the epistles- contrast specifically the “old” Mosaic covenant of sacrifices and performances with the “new” Christian covenant of grace; the Law of Moses is fulfilled and superseded by the Law of the Gospel. If the Book of Mormon’s claim to be “Another Testament [Covenant] of Jesus Christ” is read in this light, it seems to try to diminish or replace the centrality of Christ’s atonement by asserting another God-given law!
In all honesty, I’m tempted to think that “Another Testament of Jesus Christ” was chosen due to the supposed testament/testimony synonymy. In fact, translations of the subtitle that cannot use a Romance cognate of "testament" show that "testimony" is, indeed, the desired meaning: in Arabic you get شهادة, shahada, the same word used by Muslims for their declaration of faith, and in Greek you get the word that has come down to us in English as martyr - both of which mean "witness," not "covenant." But it does raise the question: does the Book of Mormon present “Another Covenant of Jesus Christ”? If so, what is that covenant?
Some latter-day revelations might give us hints on this matter. The famous scripture Ezra Taft Benson used to kickstart serious study of the Book of Mormon, for example, was Doctrine and Covenant 84:57, in which the Lord says to Joseph Smith, “and [the whole church] shall remain under this condemnation [brought about by “vanity and unbelief,” v. 55] until they repent and remember the new covenant, even the Book of Mormon and the former commandments which I have given them, not only to say, but to do according to that which I have written.” Unfortunately, we are left uncertain as to the identity of the “former commandments”: are these Joseph Smith’s revelations, or the Bible? As it is addressed to the LDS church at the time, I’m leaning toward the former. But how, then, can the Book of Mormon and the “former commandments,” which are necessarily texts, be covenants in themselves?
On a basic level, it seems like D&C 84:57 is an injunction against hypocrisy; the scriptures put their readers under condemnation if those readers profess belief but do not act accordingly. That’s a very general covenant, though. Perhaps one of the few other D&C passages to refer to the Book of Mormon, 20:8-12, could give another hint. In reiterating the event leading up to the founding of the church, D&C 20 notes that the Book of Mormon “was given by inspiration, and is confirmed to others by the ministering of angels, and is declared unto the world by them— Proving to the world that the holy scriptures are true, and that God does inspire men and call them to his holy work in this age and generation, as well as in generations of old” (D&C 20:10-11). In these verses, it seems like the very existence of the Book of Mormon obligates the believer to certain corollaries: angels minister, God still inspires and calls men, the holy scriptures are true. This could be relevant to talk of a “Book of Mormon covenant,” a covenant to believe in God and His prophets, past and present, Jewish, Christian, and Mormon – note that the condemnation from ignoring the Book of Mormon was brought about by “vanity and unbelief.”
This would fit with historical Mormon usage of the Book of Mormon; namely, it has most often been used as proof of Joseph Smith’s prophetic calling instead of a source of doctrine. However, there is one strand of thought in the Book of Mormon that gives weight to this idea that its covenant dictates a belief in continued divine inspiration.
Chronologically, the Book of Mormon starts out in a Judaic setting with mysterious visionary prefigurations of Christianity. After the Lehites leave Jerusalem, the “Messiah” becomes increasingly identified with a specific historical figure yet to come, and by the time Nephi’s brother Jacob is preaching, he begins using the title “Christ” to speak of this future savior. Nevertheless, the righteous peoples strive to keep the Law of Moses, living a sort of bizarrely Christian-inflected Judaism. When one man, Sherem, questions Jacob’s focus on this Christ by arguing that he is adulterating the Law of Moses, he is smitten by God, and Jacob’s Judeo-Christian liminality carries the day. When some, after the sign of Christ’s birth, argue that the Law of Moses should be done away with, they are convinced otherwise by those who assert that “the law was not yet fulfilled.” When Christ, having completed His sacrifice, appears to them, only then does he give them permission to move ahead from the Mosaic Law. Thus, in the Book of Mormon the righteous actors were very attentive to how God had instructed them to live, practicing rituals with full knowledge that someday, at the appropriate time, they will be “fulfilled”; that God had not ceased speaking, and could still add to His truth revealed. (2 Nephi 29 has some strong words to those who would say otherwise.)
While this may not be what the authors of the subtitle had in mind, this dedication to God’s continuing revelations is implicit and necessary if one accepts the Book of Mormon - as a signifying text, or the narrative related therein. To declare in unbelief that God has ceased speaking or calling people to preach on His behalf would be breaking that nigh-covenantal dedication.
So while the Old Covenant prefigures Christ and the New Covenant presents Him, the Other Covenant bridges the two, providing a model for faithful liminality then and in the future – in our day.