This is a widely misinterpreted and taken out of context chapter and as most of the things Paul wrote it is used to justify disobedience.
Most christians love to scream to everybody's faces "Stop sinning!" but they don't have a clue of what sin is according to scriptures.
What's the definition of sin according to scriptures?
"Whomsoever committeth sin transgresseth also The Law: for sin is transgression of The Law. - (1 John 3:4)
There it is in the new testament, the only half of the book most christians care about, so you can't get away of this definition. This means that if Paul was teaching believers to forget about the Law of God he was then sending them to sin. And I think everyone agrees that this wasn't the intention.
Now having in mind the definition of sin if we bother to go some verses previous to 3:3 we found out that in the previous chapter He actually clarified that he wasn't sending anyone to sin.
"But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid." - (Galatians 2:17)
Yeshua never told anyone to break The Law of God but to keep it by telling them to stop sinning. Believing in Yeshua won't justify breaking God's Law, as Paul said Yeshua wasn't minister of sin. But then what law was Paul talking about on this chapters?
Paul was a pharisees and pharisees had their own set of rules and regulations, result of adding to and taking away from God's Commandments and then teaching this set of man made rules as if they were God's Commandments. That was the law Paul was referring to and against this men-made laws Yeshua taught. Because living under the inventions of these men was indeed slavery and the teaching of Yeshua made us free from following men's traditions and regulations because they weren't given by God to beging with. But against the Commandments of God Yeshua never spoke, because following The Law of the Almighty set us apart from sin.
May The Creator of the universe have mercy and compassion of us all and may He be the one to guide us through the process of understanding His Word, because is not easy when we have being raised in the widely spread misconceptions and lies that the majority of believers seems to be agree with. I'm not going to lie, this is a lonely path but better being all alone in this world if that means that I'll be closer to YHVH and I'll be pleasing Him with my obedience, in the best of my abilities.
After all, Yeshua said "For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law. And a man's foes shall be they of his own household". Why you all think that will be? The moment you decide to truly be set apart and keep the Commandments of God and not the family traditions, or what pastors and other religious figures teach, everyone is going to turn their backs on you and then you'll have to make a choice. I chose YHVH.
But let's pray to God so is He Himself our teacher.