2 Thessalonians 3:14-15
If anyone does not obey what we say in this letter, take note of that person, and f have nothing to do with him, that he may be ashamed.
g Do not regard him as an enemy, but h warn him as a brother.
English Standard Version (ESV) The Holy Bible, English Standard Version Copyright © 2001 by Crossway Bibles, a division of Good News Publishers.
2 Thessalonians 3:6
Now we command you, brothers, in the name of our Lord Jesus Christ, that you keep away from any brother who is walking in idleness and not in accord with the tradition that you received from us.
You shall not hate your brother in your heart, but you shall reason frankly with your neighbor, lest you incur sin because of him.
If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother.
1 Thessalonians 5:12
We ask you, brothers, to respect those who labor among you and are over you in the Lord and admonish you.
1 Thessalonians 5:14
And we urge you, brothers, admonish the idle, encourage the fainthearted, help the weak, be patient with them all.
As for a person who stirs up division, after warning him once and then twice, have nothing more to do with him.