2 Thessalonians 3:6, 13

Now we command you, believers, in the name of our Lord Jesus Christ and by His authority, that you withdraw and keep away from every brother or sister who leads an undisciplined life and does not live in accordance with the tradition and teaching that you have received from us.

And as for [the rest of] you, believers, do not grow tired or lose heart in doing good [but continue doing what is right without weakening].