I’m sure many of our churches miss the “mark” of church discipline for a variety of reasons — they don’t have the stomach for it, fear the consequences, lack confidence in the biblical imperative, etc. But I’m also sure that many churches flounder in their discipline because they intuitively know they lack the standing to exercise the authority granted to them by Christ himself (Mat 16:18-19; 18:15-20). Consider two examples:
1) Discipleship — This is an increasingly difficult feature to cultivate in today’s local church. Discipleship requires time, personal involvement, patience, and many other personal commodities that we loath to relinquish. But discipleship is the means by which we instruct, encourage, correct, and even rebuke a brother so that we spare him (and us!) the pain of a more severe discipline down the line.
When a local church fails to cultivate a spirit of discipleship in the body they will often find themselves at a disadvantage when serious discipline is required. By failing to care for a member in the midst of a struggle against sin it becomes that much more difficult to show our concern by turning him out (1Cor 5:1-5). Should we actually excommunicate a member without prior intervention we show ourselves to be half-hearted followers of Christ.
2) Meaningful membership — Ever tried to discipline someone else’s kid? Awkward to say the least. Why should we be surprised to find that the absence of meaningful membership in a local church would create a similar tension in the face of sin. The church is responsible to care for her own which means that something should be said for knowing who belongs to whom.
It only stands to reason that Paul assumed a church was able to identify its members when he instructed a church to put a man out (1Cor 5:9-12) or not to associate with him (2Thess 3:14). Furthermore, it also stands to reason that those who were put out or “disfellowshipped” were able to notice a difference when it happened. That can’t happen in a church with mere attenders.