Jesus gives us the procedure for church discipline
"If your brother sins against you, go and show him his fault, just between the two of you. If he listens to you, you have won your brother over. But if he will not listen, take one or two others along, so that ‘every matter may be established by the testimony of two or three witnesses.’ If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, treat him as you would a pagan or a tax collector. "I tell you the truth, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven" (Matthew 18:15-18).
Jesus commends the church for faithful discipline
"I know your deeds, your hard work and your perseverance. I know that you cannot tolerate wicked men, that you have tested those who claim to be apostles but are not, and have found them false" (Revelation 2:2).
Jesus rebukes the church that does not discipline
"Nevertheless, I have a few things against you: You have people there who hold to the teaching of Balaam, who taught Balak to entice the Israelites to sin by eating food sacrificed to idols and by committing sexual immorality. Likewise you also have those who hold to the teaching of the Nicolaitans. Repent therefore! Otherwise, I will soon come to you and will fight against them with the sword of my mouth" (Revelation 2:14-16).
Restore (with gentleness) one who has fallen
"Brothers, if someone is caught in a sin, you who are spiritual should restore him gently. But watch yourself, or you also may be tempted" (Galatians 6:1).
Seek to save an erring sinner
"My brothers, if one of you should wander from the truth and someone should bring him back, remember this: Whoever turns a sinner from the error of his way will save him from death and cover over a multitude of sins" (James 5:19-20).
Forgive and restore one who repents; love him
"Now instead, you ought to forgive and comfort him, so that he will not be overwhelmed by excessive sorrow. I urge you, therefore, to reaffirm your love for him" (2 Corinthians 2:7-8).
Do not fellowship with one who will not repent
"But now I am writing you that you must not associate with anyone who calls himself a brother but is sexually immoral or greedy, an idolater or a slanderer, a drunkard or a swindler. With such a man do not even eat" (1 Corinthians 5:11).
Excommunication is sometimes necessary
(1 Corinthians 5:1-13; 2 Thessalonians 3:14)