Now we command you, brothers, in the name of our Lord Jesus Christ, that you withdraw yourselves from every brother who walks in rebellion, and not after the tradition which they received from us.
From every brother that walketh disorderly - compare the notes, 1 Corinthians 5:11-13. A “disorderly walk” denotes conduct that is in any way contrary to the rules of Christ. The proper idea of the word used here (ἀτάκτως ataktōs), is that of soldiers who do not keep the ranks; who are regardless of order; and then who are irregular in any way. The word would include any violation of the rules of Christ on any subject.