How to ID false teachers

 For when they speak great swelling words of vanity, they allure through the lusts of the flesh, through much wantonness, those that were clean escaped from them who live in error. While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage. 2 PETER 2:18-19

These are murmurers, complainers, walking after their own lusts; and their mouth speaketh great swelling words, having men's persons in admiration because of advantage. JUDE 16.

And that because of false brethren unawares brought in, who came in privily to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage. GALATIANS 2:4

The errors that false teachers follow one of two paths. Peter and Jude are writing about the antinomians. These men are teaching that once you're a Christian, anything goes. We are completely free to do as we will. Want that sports car, brother? Zoom on over to the dealership, take out a loan you can't afford, and drive it away! Want that Gucci handbag, sister? Well, why not? You should look good, right? What is wrong with this picture? Hint: It's NOT the objects being considered, but the unsanctified desire with which they are being pursued. As Jude says, these teachers are walking after their own lusts. They do not love the LORD, they are using Him as their personal ATM. They pay no attention to St John's warning about not loving the world. Peter calls them "servants of corruption", for indeed they do preach a form of the Gospel that appeals to worldly, carnal people who give lip service to being believers, but who have never met the Lord Jesus Christ. These men don't know Jesus, and worse they are corrupting the Gospel so that their hearers will fall under the same illusion. A dark, dark judgment is sure to come upon them. 

The apostle Paul, on the other hand, was being attacked by the opposite error, legalism. Paul was a bulldog when he found out "ravenous" wolves were following along behind him. He knew why: the message of freedom was unfathomable to the religious crowd. Paul says "we preach Christ crucified, unto the Jews (the religious) a stumbling block and unto the Greeks (non-religious) foolishness" I Corinthians 1:23. The message of total freedom in Christ came, as it were, out of nowhere. Paul did not find it in the Septuagint. He did not get it from Gamaliel. No man taught him. Instead, he writes to the Galatians, he got it directly from Jesus Christ Himself. 

But the religious crowd just could not handle it. The issue of circumcision was the spark that caused the great Jerusalem council found in Acts 15. I can understand them. All their life they had lived under a set of rules. The Jews were to be separate, not like the Gentiles in any way. They were not even to eat dinner with them. And now this Paul is claiming keeping the law actually detrimental to being saved. Galatians 5:2 - If ye be circumcised, Christ profits you nothing. 5:4, ye are fallen from grace, Christ is become of the effect unto you. So Paul's enemies, perhaps well intended, were following along behind him to correct his "error". 

Antinomian and legalistic false teachings are in many ways opposite. One encourages hedonistic pleasure, while the other rigid adherence to a moral code. But saints, here is what they have in common: their followers are carnal. They don't know Christ. If they did, their hearts would automatically be in lock step with Him. They would not pursue worldly pleasure because "friendship with the world is enmity with God", James 4:4. Nor would they insist on adding ANYTHING to the Gospel. No law, no rules, just Jesus, and Him crucified (I Corinthians 2:2). 

Saint Augustine once wrote, "Love God and do as you please". I think this pretty much sums it all up. If we love Him, we will obey Him. Hedonism will not appeal to us, and legalism will not restrain us. We are completely free, ironically, because we have become bondslaves of the Lord Jesus Christ. The world thinks this foolish. The carnal religious crowd finds it offensive. But here we must stand, saints. We can go nowhere else.