Sincerity and Proverbs 14:12
Proverbs 14:12 reads, "There is a way that seems right unto a man, but the end thereof are the ways of death."This verse clearly shows it possible for a man to be doing what he thinks is right in religion, but not actually be doing what God says is right, and thereby be heading for spiritual death. Sincerity by itself is not enough. Paul was sincerely religious while he was persecuting Christians (Acts 23:1, 22:3-4), but he was wrong/lost nonetheless (Acts 22:16). Even today many think they are saved because they call upon God, or believe in Jesus to some extent, but are actually lost because they do not obey God's will (Matthew 7:21). It is not enough to call Jesus Lord (Luke 6:46), we must actually do what God's word says (James 1:22ff, Acts 10:35). Genesis 37:31-36 records the case where Jacob truly felt like his son Joseph was dead, but Joseph was actually still alive. So our feelings are not necessarily reliable. They can be deceived just like Jacob's feelings were deceived. Just because you feel you are saved, that doesn't mean it is so. Only by comparing your life to God's written word can you tell if you are in a right relationship with him (Revelation 20:12). Jesus is only the author of eternal salvation to those that obey him (Hebrews 5:9).