One of the main justifications for this claim is Revelation 22:18-19, which reads,
"For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book:John says that we are not to add to, or take away from, 'the book of this prophesy", or God will send plagues our way and remove us from the Book of Life.
And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book."
But what does he refer to when he says, "the book of this prophesy?" It is commonly assumed that he refers to the Bible. The argument even depends on that assumption, but what is the Book of this Prophesy?
It is unlikely that it refers to the Bible, because the Bible didn't exist at that point. It is generally accepted that The Book of Revelation was written in about 95 AD. The Bible didn't exist until around the 4th century AD.When John speaks of "the book of this prophesy," he could not have been referring to The Bible. It didn't exist yet.
The only book in existence at the time of his writing, which contained "this prophesy" was the book he was writing, The Revelation.
This interpretation is further supported by the fact that this injunction against adding to the word of God had been given before. An often quoted instance is Deut. 12:32
"What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it."If it were true that this referred to all of God's word, rather than the specific book or section in which it is found, then every sacred writing after this point would then be false. In attempting to disprove Mormonism, the argument effectively disproves Christianity and most of Judaism.
This command is also repeated in Proverbs 30:6, but if the injunction in Deuteronomy referred to the collected works up to that point, then this command, as well as the instance in Revelation, is also invalid because it an addition to scripture.
In addition, even the Bible seems to disagree with this interpretation. Among other things, Revelation describes to individuals in the Last Days who are specifically referred to as extra-biblical "prophets". Revelation 11:10 says,
"And they that dwell upon the earth shall rejoice over them, and make merry, and shall send gifts one to another; because these two prophets tormented them that dwelt on the earth."If we apply the interpretation that revelation is finished, then we now have the Bible testifying of future prophets who will somehow prophesy without receiving the word of God. Prophets who don't prophesy.
The history of these churches also testifies that this interpretation is wrong. Early church fathers added to, and subtracted from, canon all the time. There is literally not a church in existence today which has not done it. Even the formation of the original Bible would have been a violation.
Scripture was added to collections previously recognized as the word of God countless times during the development of the Old Testament, and during the development of the New Testament. Church leaders and founders took existing, recognized canon and added whole books, or took books away. Clearly they did not interpret this as it is read today.
Critics of the Book of Mormon also sometimes say that the argument that the command refers to a specific book, or section of a book, rather than the Bible as a whole, still discredits Joseph Smith because his Joseph Smith Translation of the Bible did just that.
However, that reasoning clearly doesn't hold water because countless "true" Christians have come out with their own translations of the Bible, each of which has numerous alterations to the text, and yet none of these fall under this criticism.
The Book of Mormon cannot be criticized on the grounds of violating the warning in Rev. 22:18. If this criticism were valid, then most of the Bible would then be invalidated. In addition, the Bible clearly speaks of prophets other than those in the Bible, thus revelation must continue after Bible times, otherwise, the Bible is invalidated. Finally, numerous church fathers in history have added or omitted entire books from canon and modern Christians routinely make alterations without criticism.