Christians, is it possible that some people claiming to believe in God - really doesn't or have sold out?

Yes there are millions of religious people who ignore going house to house preaching the good news of the kingdom,which is a direct order by God. Matthew 24:14 - Acts 5:42 Acts 20:20. Also they don't obey what 1 Corinthians 5:9-13 says about disfellowshiping an unrepentant sinners.They prefer to consent sin and promote it. You can add to that that the Bible says that we should love one another not kill one another in wars. John 13:35.