Even true believers can be undermined by error. Once suspicion has entered in place of faith, then it is very hard to remove. But Paul does not get angry or threaten them. He goes about seeking their recovery in a spiritual manner. We battle not against flesh and blood with human argument alone, but against principalities and powers and therefore use the full armour of God. Just as God alone could bring them to faith in the first place so God alone could restore them. We must therefore approach the backslider with the only weapon that has any hope of succeeding: the truth of the gospel, mixed with prayer and deep concern.
We cannot hope to deliver those who have fallen into error if we are so afraid of offending them that we cannot bring ourselves to openly condemn the false doctrine which they have been taught. They cannot be helped by pretending that there is some good mixed with the error. We cannot flatter them into turning back to the truth, but we must confront the error and reveal the poison in it for what it is.
Perhaps we imagine that the truth of God is so strong that it will prevail when mixed with error? That is not how Scripture teaches us to see it. The gospel is certainly powerful so long as it is kept pure, and God’s people are mighty as long as they preserve the purity of the gospel, but begin to add a little error and the gospel suddenly becomes weak and useless. This is what Paul means when he later says, ‘A little leaven leaveneth the whole lump’ (Galatians 5:9). Christ is not content to share his people with Satan, and neither is Satan content to share them with Christ. Both seek exclusive possession of the man’s heart. God will make no alliance with sin or with error.
The biblical doctrine of separation is based upon this inability to mix truth and error. How can God’s people have any fellowship with those who teach another gospel? They must separate. Though there is human kindness shown to the lost, there can be no spiritual agreement with them. But doesn’t this raise a serious problem? Doesn’t it mean that God’s people must be ever searching until they find the perfect church, for there is imperfection and sin in every gathering of God’s people. This issue is raised by those who dislike the biblical doctrine of separation and push it to an extreme in order to ridicule it. But they show by saying such things how little respect they have for the Scripture which undoubtedly teaches separation; they are too impatient to sit down and study to find out what it really teaches on this subject. The Scripture distinguishes between those things which are grounds of separation and those things which are not. Quite clearly the Galatians were commanded to separate from the Judaizers and have nothing to do with the false gospel that they promoted - ‘Let him be accursed’. But those sins which the believer will spend a lifetime fighting against cannot be grounds of separation.
Does this mean then that some sins are more serious than others? Yes, certainly. Does this mean that we can forget about the minor sins and only give attention to the major sins and errors? By no means! Paul sought to present the churches perfect before Christ. All of Christ’s commandments are important. None can be ignored, but the pastor goes about the process of teaching the church and fostering their sanctification in an enlightened way which leaves room for continued change in behaviour concerning lesser matters.