The Bible gives us two reasons for totally purging people from our lives and fellowship: (1) unrepentant sin and (2) heresy.
Concerning sin, Paul tells the Corinthians, “Purge the evil person from among you” (1Co 5:13). If someone persists in their sin with no signs of repentance even after we’ve tried everything to restore them, Paul says they must go. “Do you not know that a little leaven leavens the whole lump?” (1Co 5:6). Allowing blatant sin to remain in the church is a recipe for disaster because it spreads.
Concerning heresy, the Bible pulls no punches. The problem is that we’re tempted to label every theological disagreement a matter of heresy. Worse yet, we struggle to discern between false teachers (i.e., wolves) and misled ignorant sheep. Let me give you a sample of what the Bible says about false teachers from 2 Peter 2:
But false prophets also arose among the people, just as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Master who bought them, bringing upon themselves swift destruction. And many will follow their sensuality, and because of them the way of truth will be blasphemed. And in their greed they will exploit you with false words. Their condemnation from long ago is not idle, and their destruction is not asleep. (2 Peter 2:1-3)
They will deny Jesus Christ, deceiving people for their personal gain. We can’t throw everyone we disagree with into that category. That’s a deadly serious charge. It’s a real threat, but we should be cautious about who we label a heretic.