For those who think since we are under the Law we don't have to follow it anymore, sin doesn't matter, and they do not understand grace or the Law of God.
Because we are under grace the Law that condemned us before lives in us. The Law Giver Jesus Christ lives in us so before we were afraid of the Law now it has become a part of us and we love it.
Grace and mercy are not for those who love and defend their sin, those who think like this are not born again and are on their way to hell.
1 John 3:7-9 "…7 Little children, let no one deceive you: The one who practices righteousness is righteous, just as Christ is righteous. 8 The one who practices sin is of the devil, because the devil has been sinning from the very start. This is why the Son of God was revealed, to destroy the works of the devil. 9 Anyone born of God refuses to practice sin, because God’s seed abides in him; he cannot go on sinning, because he has been born of God.…"
When we see someone who defends sin claiming to be under grace we are experiencing someone who has not been born again. Those who are born again love Christ Who lives in them and hates sin of every sort. When they fall themselves they confess to be cleansed.
1 John 1:9
"9 If we confess our sins, He is faithful and righteous, so that He will forgive us our sins and cleanse us from all unrighteousness."
This passage was written to believers who want to be cleansed, not unbelievers who love their sin and even defend it.