2 John 1:10

If any one comes to you and brings not this doctrine, receive him not into your houses, and salute him not;

Titus 3:10

A man that is a heretic, after the first and second admonition, reject,

Galatians 1:8-9

But if we or an angel from heaven preach you another gospel contrary to what we have preached you let him be accursed.

Romans 16:17-18

I exhort you, brothers, to observe those that cause dissensions and offenses contrary to the teaching which you learned, and avoid them;

1 Corinthians 5:11

But now I have written to you not to associate, if any one called a brother is a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or rapacious, even to eat with such a one.

2 Thessalonians 3:6

And we charge you, brothers, in the name of our Lord Jesus Christ, to withdraw from every brother who walks disorderly and not according to the tradition which you received from us.