2 John 1:9-11

1:9 Everyone who goes on ahead and does not remain in the teaching of Christ does not have God. The one who remains in this teaching has both the Father and the Son. 1:10 If anyone comes to you and does not bring this teaching, do not receive him into your house and do not give him any greeting, 1:11 because the person who gives him a greeting shares in his evil deeds.