2 Thessalonians 3:6, 14-15

Now we command you, brethren, in the name of our Lord Jesus Christ, that ye withdraw yourselves from every brother that walketh disorderly, and not after the tradition which they received of us.

And if any man obeyeth not our word by this epistle, note that man, that ye have no company with him, to the end that he may be ashamed. And yet count him not as an enemy, but admonish him as a brother.