Paul wrote to the church at Rome and told the believers, “Now I urge you, brethren, note those who cause divisions and offenses, contrary to the doctrine which you learned, and avoid them” (Romans 16:17). He told Titus, “Reject a divisive man after the first and second admonition, knowing that such a person is warped and sinning, being self-condemned” (Titus 3:10-11). He told the Corinthians, “But now I have written to you not to keep company with anyone named a brother, who is sexually immoral, or covetous, or an idolater, or a reviler, or a drunkard, or an extortioner--not even to eat with such a person” (1 Corinthians 5:11).
Taken together, these verses tell us that it is sometimes necessary to avoid, reject, and not keep company with another member. This may not be comfortable for some people, but it is necessary at times for the sake of the offending person. Notice the offenses Paul named: causing divisions and offenses among God’s people, being divisive, and practicing sins such as fornication, covetousness, idolatry, etc. This is not referring to people who are trying to live right but have taken an unintended fall (see Galatians 6:1). This is referring to people who are continuing in these practices without repentance. Such people must not be treated as though everything is okay between them and the Lord. They need to be forced into seeing the reality that they are not behaving like Christians. This happens, hopefully, when the body stops keeping company with them.
Avoiding, rejecting, and not keeping company do not necessarily mean there can be absolutely no contact or conversation. It simply means that you keep such people at a distance, you don’t permit them into your intimate fellowship. You may greet them if you see them, but should not get together for dinner...not until there is clear repentance which is recognized by the assembly as a whole.