Sincerity doesn’t make something true

“It makes no difference what you believe, just as long as you are sincere? This is the philosophy of many people today but it is not what the Bible teaches. Sincerity doesn’t necessarily make something true. Suppose I feel sick in the night and go to the medicine cabinet to get some stomach medicine. Not being fully alert and in the darkness of the night I get a bottle I think is pepto-bismal. Instead it is boric acid and I become violently ill and almost die. I was sincere but the medicine was wrong. In the same way it makes a difference what I believe about Christ. (Lou Nicholes - Missionary/Author).