Warn them that are unruly.
Unruly can be translated “disorderly” or “insubordinate.” Paul was instructing the believers in Thessalonica to warn those who would not listen to the teachings of the Scriptures. Later, in the second letter, Paul instructs them to have no social fellowship with any who rejected the truth. Society today has little or no recourse against those who are insubordinate. Human rights allow a person to say or do almost anything. But God frowns on the disorderly Christian. We must respect God-given authority.