Several key scriptures form the basis for disfellowshipping. Jesus himself introduced the standard:
Matthew 18:15-17 : “Moreover, if your brother commits a sin, go lay bare his fault between you and him alone. If he listens to you, you have gained your brother. 16 But if he does not listen, take along with you one or two more, in order that at the mouth of two or three witnesses every matter may be established. 17 If he does not listen to them, speak to the congregation. If he does not listen even to the congregation, let him be to you just as a man of the nations and as a tax collector.”
Jesus did not say to never utter a word to an unrepentant wrong doer. Rather, he stated they should be treated as persons of the world. Though not considered close friends, Jesus himself spoke to and ate with tax collectors. (Matthew 9:11) The majority of information on how to treat wrongdoers within the congregation comes from Paul. Paul showed a balanced approach advising not to socialize with a wrongdoer but to still ‘admonish as a brother’. 2 Thessalonians is key to understanding that wrongdoers should be marked, not disfellowshipped.
2 Thessalonians 3:6, 14-15: “Now we are giving YOU orders, brothers, in the name of the Lord Jesus Christ, to withdraw from every brother walking disorderly and not according to the tradition YOU received from us…. 14 But if anyone is not obedient to our word through this letter, keep this one marked, stop associating with him, that he may become ashamed. 15 And yet do not be considering him as an enemy, but continue admonishing him as a brother.”
Paul did not say to disfellowship such people, but rather instructed the congregation to ‘mark’ or ‘take note of’ such a person, yet “continue admonishing him as a brother”. Hence Paul did not indicate that marking was only for non-serious sin. The Society’s disfellowshipping policy has been formulated mainly from statements in 1 Corinthians 5:11 and 2 John 10. At 1 Corinthians Paul specifically outlined practices for which to cease ‘mixing’ with a brother. Yet this too is similar to the advice given when marking a brother.
1Corinthians 5:11: “But now I am writing YOU to quit mixing in company with anyone called a brother that is a fornicator or a greedy person or an idolater or a reviler or a drunkard or an extortioner, not even eating with such a man. 12 For what do I have to do with judging those outside? Do YOU not judge those inside, 13 while God judges those outside? “Remove the wicked [man] from among yourselves.””
1 Corinthians does not say to totally shun a brother who is a wrong doer, rather it says to ‘quit mixing in company’ with such a person and ‘not eat with’ such a man. This statement does not state that this type of person must never be spoken to. By far the strictest advice on how to treat individuals denying Jesus was given by John. It is on the basis of this scripture that treatment of disfellowshipped ones is primarily based. However John was here referring to a specific type of person in a unique situation.
2 John 7-11: “7For many deceivers have gone forth into the world, persons not confessing Jesus Christ as coming in the flesh. This is the deceiver and the antichrist. 8 Look out for yourselves, that YOU do not lose the things we have worked to produce, but that YOU may obtain a full reward. 9 Everyone that pushes ahead and does not remain in the teaching of the Christ does not have God. He that does remain in this teaching is the one that has both the Father and the Son. 10 If anyone comes to YOU and does not bring this teaching, never receive him into YOUR homes or say a greeting to him. 11 For he that says a greeting to him is a sharer in his wicked works.”
A far harder line appears to be given here than by either Jesus or Paul, as it is stated not to even greet such a person. Who is John referring to? The Antichrist. It is only in regard to the Antichrist that instruction was given not to even greet a person. John is not here referring to wrongdoers such as fornicators and greedy people. Nor does he mention those that reject the authority of an organization. He simply applies this to those that reject Jesus. The Watchtower Society uses this single scripture in 2 John to dictate that every disfellowshipped or disassociated person should not even be greeted.
Morph
(fyi - much of this was paraphrased from a site i visited months ago and developed a document from. so if it looks familiar it may be - i didn't want to take credit for the development of it)