Testing False Teacher: don't ask what they affirm, see if they demonstrate submission to Christ

 "But the supreme and unthinkable heresy is to say no to His sovereign lordship. This is the matter at hand. Here are people who probably won't deny the deity of Christ, who probably won't deny His atonement outwardly, even though they may deny it inwardly, who probably won't take a position against the virgin birth and the bodily resurrection, who may not deny the Second Coming, may even preach it. They may name Christ, claim Christ, serve in His name, preach His name, cast out demons in His name, do many wonderful works in His name, but they say no to His...what?...to His lordship. What does that mean? That means they will not submit their lives to His rule.

The issue here, beloved, is primarily not theologically, it is ethical. It is not their theology that unmasks them, it is their morality that unmasks them. You understand that? It is not their theology that...that is covert. It is their morality that unmasks them."

Now the idea, people, is this is very crucial. When you are identifying a false teacher sometimes you can't tell by their theology, you have to look past that to their morality. And you are not asking what they affirm, for they may affirm that Christ has bought them. You ask...do their lives demonstrate submission to the sovereign Lord?

Listen, they attract people, they attract people with their talk about Christ and their talk about belonging to Christ, but they don't want to submit to sovereign lordship. They want freedom to live the way they want to live. They want liberty to live the way they want to live. They don't want anybody impinging on their conduct. And so many people are led astray into a kind of Christianity that knows nothing about submission to the sovereign Lord. That's exactly what you have in Matthew chapter 7, exactly. "Not everyone who says to me `Lord, Lord,' will enter the Kingdom of heaven, but he who...what?...does the will of My Father." 

~ John MacArthur, A Portrait of False Teachers Part 2 


This is calls for the spiritual gift of discernment by knowledge and faith in the Scriptures to be able to know the difference between right and almost right.