Both the Mormons and the fundamentalist Protestants err by believing that the Church founded by Christ can apostatize
2 Thes. 2: 33 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
It's a requirement of the return of the Lord.
Problem: neither the Armenians, nor the Chaldean Church of Iraq, nor the "Mar Thoma" Christians of India, nor the Ethiopians were ever under Constantine or any other Roman Emperor. All of them claim to have been, and probably were, founded in the Apostolic era.
I said it was the clearest and easiest to point to, not only.
None of them are remotely like Mormonism or fundamentalist Protestantism. However, they do all bear a significant resemblence to Catholicism and Eastern Orthodoxy. (Many of the Chaldeans and "Mar Thoma" Christians are today in communion with the Pope of Rome.)
Yeah, they borrowed a lot from the wrong places, didn't they.
Let God be true, and both Martin Luther and Joseph Smith be liars.
God is a God of truth and cannot lie. He told me what to do, what to join, what to believe. compared to him, you are... unconvincing, and I am being kind.