Seems evident from this verse that there are no other gospels or testimonies from anyone no matter what they say! The front of the Book of Mormon now says that it is “Another Testament of Jesus Christ”. Ask your Mormon friend what his thoughts are about this predicament.
Joseph Smith said; “Take away the Book of Mormon and the revelations, and where is our religion? We have none”. Teachings of the Prophet Joseph Smith, pg. 71.
In other words, there is nothing inside of this religion that has anything to do with Jesus Christ.