Which roman pope said that if Roman Catholic Church is not the true church on earth then it is the church of Jesus Christ of latter day saints?

Answer 1

No pope said this, it was a Catholic scholar. The quote originally comes from a pamphlet entitled "The Strength of the Mormon Position" published by Mormon Apostle Orson F. Whitney in 1917. It was repeated in the book "A Marvelous Work and a Wonder" by Mormon Apostle LeGrand Richards (first published in 1950).

The exact quote is as follows:

"Many years ago a learned man, a member of the Roman Catholic Church, came to Utah and spoke from the stand of the Salt Lake Tabernacle. I became well-aquainted with him, and we conversed freely and frankly. A great scholar, with perhaps a dozen languages at his tongue's end, he seemed to know all about theology, law, literature, science, and philosophy. One day he said to me: "You Mormons are all ignoramuses. You don't even know the strength of your own position. It is so strong that there is only one other tenable in the whole Christian world, and that is the position of the Catholic Church. The issue is between Catholicism and Mormonism. If we are right, you are wrong, and if you are right, we are wrong; and that's all there is to it. The Protestants haven't a leg to stand on. For, if we are wrong, they are wrong with us, since they were a part of us and went out from us; while if we are right, they are apostates whom we cut off long ago. If we have the apostolic succession from St. Peter, as we claim, there is no need of Joseph Smith and Mormonism; but if we have not that succession, then such a man as Joseph Smith was necessary, and Mormonism's attitude is the only consistent one. It is either the perpetuation of the gospel from ancient times, or the restoration of the gospel in latter times."

A digital copy of the pamphlet this was originally published in is available for free through the "Related Link" below (hover over the red "ebook-free" button on the left side of the page, then click on the format you want).