2 John 1:9-11

9 A person must continue to follow only the teaching of Christ. If he goes beyond Christ’s teaching, then he does not have God. But if he continues following the teaching of Christ, then he has both the Father and the Son.

10 If someone comes to you, but does not bring this teaching, then do not accept him into your house. Do not welcome him.

11 If you accept him, you are helping him with his evil work.