In the "Teaching Tips" for this lesson, Greg Blake notes:

Church discipline is always open to abuse, so Paul left some principles for the Galatians to follow:
The task is not that of punishment but of restoration; the main verb in verse 1 connotes remedial action – there is no hint of retribution or punitive action.
The restoration is to take place in a spirit of gentleness. This may mean no more than just “gently,” but the Hebrews would also use this phrase to refer to the “gentle Spirit.” Thus Paul may have had in mind the energizing work of God's Spirit, one of whose marks is gentleness (5:22, 23). God promises to be with us in the healing process – not only that of the offender, but also that of the Christian whose task it is to restore.
Notice also the warning for Christians to be aware of the tendency toward arrogance as they engage in help-ing others.

Church discipline seems not to be practiced too often among churches today. Should this change?
Even if not in a formal practice of "church discipline", how can we work to restore fallen Christians, rather than further alienating them from our church and Christ?
Source: Lesson 6: "The Works of a Christian", Adult Teacher's Insights, p. 35.