(Another bit from my ongoing study of church discipline in Paul:)
For Paul, discipline in the church does not have a monolithic purpose. He sees instead a number of related outcomes, and in a given situation may emphasize one or more of them.
Clearly, Paul is concerned about the repentance and restoration of the offender, a thread which runs through most of the disciplinary passages in the Pauline corpus. For example, in 1 Cor 5:5, Paul envisions expulsion as saving the spirit of the offender in the day of the Lord Jesus – which presumes repentance – and in 2 Cor 2 speaks of the sorrow(ful repentance) and restoration of one who is arguably to be identified as the offender of 1 Cor 5. As well, Gal 6:1 describes the successful confrontation of a sinning believer as “restoration.” Additionally, in 2 Tim 2:25-26, it is hoped that gentle correction will bring repentance and restoration on the part of those who oppose the truth. Further, the false teachers in Crete are to be rebuked sharply so that they may be sound in the faith, a condition equivalent to restoration and which presumes repentance on their part (Tit 1:13).
Paul is also concerned for the holiness and purity of the congregation. This solicitude is most evident in 1 Cor 5, where the Passover analogy (5:6-8) and the likely background of the temple imagery in 1 Cor 3:16-17 provide a backdrop for Paul’s instruction. Paul’s concern for holiness in the congregation is also indicated in the Pastoral Epistles by his emphasis, in the face of false teaching, on the protection of the deposit of apostolic doctrine which had been given to the church. For instance, the Cretan errorists are to be rebuked sharply in order that they would be sound in the faith (Tit 1:13). The congregation, as individuals and as a whole, is to be pure in both doctrine and life. The confrontation and expulsion of unrepentant offenders not only removes the impure life of the offender, but also serves to warn the rest of the congregation of the consequences of unrepentant sin (cf. 1 Tim 5:20).
Consistent with other Pauline disciplinary passages, Paul also has concern for the offenders’ repentance and restoration in 2 Thess 3. This is indicated by the stated purpose of the response to the disobedient: the Thessalonians are not to associate with him in order that he might be ashamed, and this shame is best understood as potentially leading to the repentance of the disobedient.
Another purpose of Paul in ecclesiastical discipline may be gleaned from 1 Thess 4:9-12, a passage which underlies 2 Thess 3. In 1 Thess 4:9-12, Paul commands the Thessalonians to live quietly, to attend to their own affairs, and to work with their own hands – essentially the same injunctions as given or implied in 2 Thess 3:11-12. In 1 Thess 4:12, however, Paul states that his purpose in commanding these things is “that you may behave with propriety toward outsiders.” Regarding this statement of purpose, Schreiner notes that the disorderly behavior provides “a poor recommendation of the Christian faith to unbelievers,” while a proper lifestyle “enhances the witness of the community.” (Thomas R. Schreiner, Paul, Apostle of God’s Glory in Christ: A Pauline Theology [Downer’s Grove, Ill.: InterVarsity, 2001], 396). It appears that Paul would see, though more indirectly, the maintenance of Christian witness as a result of proper disciplinary action.