idolatry is based on the idea that you can do anything that will win the favor of God, aside from following his Law

vain means "without likely results" "to no useful end" it is pure window dressing and it is the root of the sin of the leader of the Fallen Angels

also, the whole point of Jesus is that you aren't doomed just because you have sin

we all have sin, but do we seek to heal it and make it holy or do we continue to defend it?