Let this story illustrate.
In 1986, one month after being called to serve as an apostle, Elder Ballard was in Bolivia and Peru for conferences. He went to visit Lake Titicaca which is the largest lake in South America. That year the lake rose 10-12 feet in a few short months destroying surrounding farm land. Over 200 LDS members had property destroyed and 40 members lost their homes as a result from the flooding. Elder Ballard and other visiting authorities stood on the shore of the lake to survey the damage. When the other authorities left Elder Ballard had a feeling to bless the land. It wasn't a vision or a voice, just a feeling. Nevertheless he followed it, and called the other authorities telling them to come back to the ground. There, near the lake, Elder Ballard offered a prayer to God and said, "By the authority of the priesthood, I command the water to recede." He returned to his hotel room that night and thought about the prayer. As a new apostle he began to be frightened because there was no where for the water to go. Experts said it would take a couple years for the water level to return to normal. He prayed again and said, "Heavenly Father, maybe i have overstepped my boundaries, but I felt prompted. Grant it to be true." In less than two months he received newspaper clippings in the mail saying, "Lake Titicaca drops an unexplanable 10 feet. It's a miracle."
And one more story about how an ordinary man is purified to be a living prophet.
At the age of 30, Elder Ballard was serving as a bishop over a congregation. One woman in his area was a widow living with her daughter. She and Elder Ballard were close and he even called her his, "Grandma Friend." Late one night after meetings in the chapel Elder Ballard got in his car to drive home. He thought of his grandma friend and felt like he should go visit her. He looked at his watch. It was ten o'clock. "It's too late," he thought, "I'll see her tomorrow." He drove home and attempted to sleep but couldn't stop thinking about her. First thing in the morning he knocked on the door of his grandma friend's home. Her daughter answered, "Oh Bishop. Thank you for coming. Mother passed away two hours ago." He said he stood on the porch and wept. He got back into his car after consoling the family and uttered a humble prayer, "Heavenly father, I will never do that again. I will not argue with you. If you ask me to do something I will do my very best to do it."
After last night, after encouragement, after counsel, after answered prayers, my testimony was fortified that after all I believe in living prophets.