Mormons* are often weird about the law of witnesses idea. (You know, the thing from Matthew 18:16, or Deuteronomy 19:15, saying that it takes two witnesses to testify of truth.) For example, to take one i heard recently, since Matthew, Mark, Luke, and John all testified that Jesus is the Christ, that proves that he was.
Of course, there’s lots of witnesses to the transcendence of the Buddha, as well.
In a different direction, i’ve also heard (happily only once, so this is an outlier) the claim that since Jesus is the Christ, the fact that both the Bible and the Book of Mormon testify of such proves that the Book of Mormon is from God, since it and the Bible both testify of truth. That one’s so flawed and circular that i still haven’t figured out how to explain how wrong it is.
*I assume that people in some other denominations do this, too, but i have no experience there.
Faith Hill: Where Are You, Christmas?
4 years ago