One of the main, and yet never considered, problems with teaching doctrines that say righteousness isn’t necessary and sin isn’t that bad, is the effect it has upon the Church, the Body of Christ.
Ephesians 4 says that a properly functioning church will have individual members growing into the perfect man Christ Jesus.
Growing into Christ means doing righteousness and not sin. I mean, seriously, it can hardly mean much else!
As individual members grow in righteousness they will not be tossed about with every wind of false doctrine–sin always leads to bad doctrine.
Good doctrinal footing will lead to more righteousness. As members grow the Body edifies itself in love. As one member grows, they help other members grow.
As you remove the beam from your eye, you can better see to remove the mote from your brother’s eye.
In other words, your spiritual growth will affect those around you.
This is one of the least considered problems with sin. Your sin affects other people.
When a Christian excuses their own sin and tries to theologically justify why their spiritual immaturity is no big deal, what they are basically saying is, “I will never be equipped to help you grow.”
If one member of the body suffers, the whole body suffers.
One immature member will keep the body immature.
It might be cute for you to maintain you’re saved by your baptism and nothing you do matters. That may relieve your guilt temporarily. It might make you feel better.
But it will also destroy you and who knows how many other people. This is especially true when such things are taught as official church doctrine.
We are teaching people to be immature, which keeps them immature, which never allows them to help others mature. It’s a devastating cycle.
Justifying your own sin with flippant false doctrines hurts you and everyone who has contact with you. If you care about others and the health of the church: grow up!