Some people believe that there are multiple realities or truths. They therefore believe that many sets of beliefs have the power to bring us back to our Heavenly Father's presence and gain eternal happiness. They believe, for instance, that repentance can be required in one church and not another, but both churches can be right. They believe that two churches can claim divine authority, and both be right.
Satan uses this idea as a weapon to keep us divided and to give people an excuse to live as they please. The Lord says there is only one faith. Christ did not set up more than one church or preach more than one gospel when He was on the earth. His followers in Jerusalem were reprimanded when factions broke out. He has reminded us in our time that he leads one church only. Indeed, one of the very purposes of his church is to unify all people in their efforts to become who He would have us become and gain eternal life.