“But it was because of the false brethren secretly brought in, who had sneaked in to spy out our liberty which we have in Christ Jesus, in order to bring us into bondage.” (Galatians 2:4)
Some people are just “different” than we are: they may look differently, have a different background and perspective, different tastes, etc. People will vary in a number of ways. But notice that Paul does not say in Galatians that his opponents were merely “different;’ he said they were “false.” There is a big difference.
The Judaiazers who opposed Paul were not just “different.” It wasn’t that they used a different kind of music for worship, or met in homes instead of a public place. That would be “different.” But these men were “false.” They were NOT brothers in Christ at all. They were teaching and practicing contrary to the basic Christian doctrine of justification by faith alone, as Paul makes clear later in this letter. They would drag Christianity back into Jewish legalism, and Paul knew when to draw the line. These men were not just “different” — they were “false” and he labeled them as such.
Christians today need this same kind of discernment and courage. Some believers practice their faith in different ways than we do — and we should exercise charity and grace towards those who do. But there are also “many false prophets who have gone out into the world,” (I John 4) who are promulgating doctrines and practices which contradict some of the most basic tenets of our faith. When we encounter them, like Paul we need to call them out for what they are: not merely “different;” but “false.”