What happens when a Christian is found to be struggling with sin? What, if anything, should the rest of the church do about that?
There are at least two extremes by which Christians respond to the sins of others, both of which, for Paul, fall short of faithfulness. The first response says "to each his own, it's none of my business, that's between the sinner and God and I shouldn't get involved.” Paul rejects the notion that we can disregard one another, because Christ never disregarded us…”even while we were yet sinners.” (Romans 5:8)
The other extreme continually puts laws, statutes, standards and roadblocks ahead of people, as if to say “you broke the rules, now you can no longer be with us.” It’s the way of ultimatum, threat, and dissociation—making a scapegoat of others in hopes of justifying our own selves. This is not the Christ way either.
All Christians are connected, "one body with many parts" (1 Corinthians 12). Paul urged the Galatian churches to remember that no one is dispensable to Jesus; we must endlessly work to restore those who've strayed into sin back to the Body of Christ. But we must always do so as Jesus did: "In a spirit of gentleness" and love. (Galatians 6:1)