Ephesians 5:11

Do not have fellowship with [people who practice] worthless deeds of darkness [i.e., sinful living], but expose them instead.

2 John 1:10-11

If anyone comes to you [i.e., to your meetings] who does not bring this teaching [about Christ], you should not welcome him into your home or give him [any] greetings [i.e., suggesting approval or endorsement].

Treasury of Scripture Knowledge

Summary

And Ahab king of Israel said unto Jehoshaphat king of Judah, Wilt thou go with me to Ramothgilead? And he answered him, I am as thou art, and my people as thy people; and we will be with thee in the war.

Bible References

I am as thou

Ephesians 5:11
Do not have fellowship with [people who practice] worthless deeds of darkness [i.e., sinful living], but expose them instead.
2 John 1:10
If anyone comes to you [i.e., to your meetings] who does not bring this teaching [about Christ], you should not welcome him into your home or give him [any] greetings [i.e., suggesting approval or endorsement].