Jeffrey R. Holland discusses the parallels between 1 Corinthians 13 and Moroni 7; argues both Paul and Moroni may have used an ancient source or it was the result of revelation to both authors.
Jeffrey R. Holland, Christ and the New Covenant: The Messianic Message of the Book of Mormon (Salt Lake City: Deseret Book, 1997), 413n46
The fact that Paul uses comparable language without having the benefit of Mormon and Moroni's text suggests the possibility of an ancient source available to both Book of Mormon and New Testament writers. It may also simply be another evidence that the Holy Ghost can reveal a truth in essentially the same words to more than one person.