Question: I’ve told unsaved friends that the Qur’an, Book of Mormon [1], etc., are false additions to the Bible. They asked me, “What is different about the many Old Testament books added to the Torah, and the New Testament to the Old?"
Response: The Qur’an, Book of Mormon [1], etc., make no claim of being part of the Bible, contradict it completely, and obviously have different authors. The entire Old and New Testaments agree with, foretell and/or fulfill each other, and clearly have the same Author.
Links:
[1] https://www.thebereancall.org/taxonomy/term/52/mormonism