The church is the family of God. 

Sin spreads.  vs. 5

⁵ Now if anyone has caused pain, he has caused it not to me, but in some measure—not to put it too severely—to all of you.

Confrontation, done correctly, demonstrates love. vs. 6

⁶ For such a one, this punishment by the majority is enough,

The goal of church discipline is restoration. vv. 7-10

7 So you should rather turn to forgive and comfort him, or he may be overwhelmed by excessive sorrow. ⁸ So I beg you to reaffirm your love for him. 

A final warning: the robbery of Satan.  vs. 11

11 So that we would not be outwitted by Satan; for we are not ignorant of his designs.

Take Home Idea:  As the family of God we have a responsibility to call out sin and call back sinners.