1 Corinthians 5:9
I wrote you in my letter not to associate with sexually immoral people.
Ephesians 5:11
Do not have fellowship with [people who practice] worthless deeds of darkness [i.e., sinful living], but expose them instead.
2 Corinthians 6:14
Do not team up with unbelievers [i.e., in close relationships, such as marriage, etc.]. For what do righteousness and wickedness have in common? Or, what fellowship can light have with darkness?
2 Thessalonians 3:14
And if any person does not obey our instructions, [given] in this letter, you should take note of him so that you do not associate with him, in hope that he will become ashamed [of his conduct].
2 Thessalonians 3:6
Now we command you, brothers, in the name [i.e., by the authority] of our Lord Jesus Christ, that you people stay away from every brother [or sister] who lives an idle life [See note on I Thess. 5:14], and not according to the [inspired] tradition which you received from us.
1 Corinthians 5:2
And you are arrogant [about it] instead [of being ashamed]. Should you not be grieved to the point of removing from your fellowship the person who has done this [terrible] deed?
1 Corinthians 5:7
Get rid of the old yeast [i.e., of sin, and especially the unrepentant sinner], so that you can be a new batch of dough, without yeast in it [i.e., a godly church without unrepentant sinners in it] as [I know] you really are. For our Passover [Lamb], Christ, has already been sacrificed.
2 Corinthians 6:17
Therefore, the Lord says [Isa. 52:11], "You people should leave their company [i.e., unbelievers, verse 14] and separate yourselves from them, and do not touch anything unclean [i.e., their evil practices], and I will welcome you."