The phrase “church discipline” conjures up ideas of trials and inquisitions, of people with big hats and big agendas about how to exclude others from the church. But Jesus delivers these instructions in the context of seeking lost sheep and forgiving seventy times seven. Our Triune God is love, three persons in one God, the divine community and source of all healthy relationships. Sin separates us from God and one another, and therefore in order to be a church that is not torn apart by sin, we have to deal with it. Most church discipline occurs informally, but it’s so necessary that the Protestant Reformers considered it a third mark of the church right after word and sacrament.