In some of your replies you say a person must ask sincerely for salvation. How can people not be sincere when they ask for salvation?
People often get carried away on a burst of emotion caused by a captivating preacher or evangelist and respond to an altar call in the passion of the moment. Later, they realize it was just a momentary thing that didn’t have any lasting meaning for them. Jesus made mention of these people in Matt. 13:20-21.
Follow up research indicates that as many as 80% of those who respond to an altar call at a crusade never become involved with a church or any other kind of Christian fellowship. The conclusion is that at least some of these people weren’t really sincere when they came forward, so it’s likely their trip to the altar didn’t result in their salvation.