"The Celestial Kingdom is so great that if you were able to see it you'd kill yourself just to get there..." – Joseph Smith the LDS (Mormon) first prophet
This is a common tale told in Mormon sermons. It is intended to inspire the parishioners into understanding glory of the Lowest kingdom of heaven, therefore inspiring the listener to wonder the glory of the Terrestrial Kingdom and the Celestial Kingdom
External Research on the subject and possible origins of the quote.