Did the Book of Mormon plagiarize the KJV Bible?

Answer 1

No. Members of the Church of Jesus Christ of Latter-day Saints (commonly called the "Mormon" church) use the KJV Bible as well as the Book of Mormon, so there is no use in copying the Bible into the Book of Mormon. There are a few quotes from the Old Testament in the Book of Mormon, most of them from Isaiah. These do not count as plagiarism, however, as it is clearly stated that they are quotes. Plagiarism is when you try to pass someone else's work off as your own, not when you quote someone else.

You can read the KJV Bible and Book of Mormon, as well as other scripture used by the Church, at the "Related Links" below.

Answer 2

It depends to some extent on the provenance of the Book of Mormon. If an angel really did bring Joseph Smith the book on gold plates, then it could not have plagiarised the KJV or any other Bible. If the Book of Mormon was actually written around 1830, there was at the very least the intention to imitate the style and language of the KJV, if only because of expectations that scripture would use old-fashioned words.
Plagiarism involves using or closely imitating the language and thoughts of another author without authorisation and presenting this without crediting the original author. It is true that the Book of Mormon was written in an 'olde Englishe' style reminiscent of the KJV Bible and shared some errors ('cherubims' and 'seraphims') found in the KJV Bible (for example Genesis 3:24; Exodus 25:18, 19, 20, 22; Isaiah 6:2, 6; Hebrews 9:5), implying that the Book of Mormon was written by someone with a knowledge of the King James Version. The errors were corrected in later editions of the Book of Mormon, but are a historical fact.

As the Book of Mormon presents an account of purported events for the most part not found in The Bible, it could be debated whether the similarities of style and content are sufficient to say that the Book of Mormon constitutes plagiarism.