2 John 1:9-11

Anyone who wanders away and does not remain faithful to the teaching of Christ has no relationship with God. But those who remain in the teaching of Christ have a wonderful relationship with both the Father and the Son. So if anyone comes into your fellowship claiming to be a true believer yet doesn’t bring this teaching, you are not to consider him as a fellow believer, nor should you welcome him into your homes. For if you welcome him as a believer, you will be partnering with him in his evil agenda.