1. There are 3 ways to leave an assembly or break fellowship:
a) To die or fall asleep in Christ or transfer to another assembly.
b) To stop attending at the assembly and separate from its members.
c) To be asked to leave by the oversight.
2. Those who leave of their own choice are in 2 categories:
a) Those troubled or ensnared by personal difficulties or sins (MATTHEW 13:18-22). Some of these may be helped by wise counsel.
b) Those who hold a grievance or difference with the assembly or some member. In fact this is never a reason to depart (see 'Biblical Christianity' sheet).
3. Those asked to leave (MATTHEW 18:17-18) will be in the following groups:
a) They are involved in immorality without repentance (1 CORINTHIANS 5:1-5; 2 THESSALONIANS 3:6).
b) They promote unsound doctrine or practices (1 TIMOTHY 6:3-5; TITUS 1:9-11).
c) They create divisions and offences with brethren or the oversight, often by tale-bearing, or unreasonable accusations, e.g. "not enough love", "who gets the money?", "others should minister", etc. (ROMANS 16:17-18; 1 TIMOTHY 5:11-18; PROVERBS 22:10).
4. Since their activities trouble others, the oversight must act to prevent a spread (2 TIMOTHY 2:16-18; HEBREWS 13:9,17; HEBREWS 12:15).
5. The attitude of assembly members toward people under 2b and 3 is much the same (Also a 2a often becomes a 2b). They must be
"avoided" (ROMANS 16:17), or
"withdrawn from" (1 TIMOTHY 6:3-5; 2 THESSALONIANS 3:6,14-15).
6. We may greet or acknowledge them in a friendly way, but should refuse to discuss their problem area or have sustained fellowship (1 CORINTHIANS 5:11; 2 JOHN 10-11). If they wish to return to fellowship, the oversight must be advised. Our attitude is as if a sheep has an infectious disease. No animosity, much concern, but separation.
7. Scripture and experience show that those who leave find it hard to return. Beware of wasting excessive time on a problem the Lord says to stand apart from - (MATTHEW 18:15-18; 1 CORINTHIANS 5:3-8,13; 2 PETER 2:1-3,19-22; HEBREWS 10:25-31; 1 JOHN 2:19).
8. Those who leave will often accuse or criticise the oversight. The pastor will not publicly criticise him (unless he is an elder, 1 TIMOTHY 5:19-20) to ease his return. If you listen you will hear one side of the story. Hence the warning to "avoid" such people. If you are troubled see the pastor privately. Don't discuss such accusations with friends (1 TIMOTHY 5:19). This spreads "a root of bitterness" (HEBREWS 12:15).
9. Spirit-filled people from other churches are normally in category 3b. The same rules apply. All these problems (see 3) are a threat to the wellbeing of the whole assembly. Much more so than private failings by members. Therefore, if your pastor has to act, support him totally by maintaining scriptural separation.
Source: 'Voice of Revival'