Whose mouths must be stopped, —-literally, "muzzled," or "bridled" as an unruly beast. It was necessary for Titus to stop the false teachers. Put away from thee a wayward mouth, And perverse lips put far from thee (Proverbs 4:24) . who subvert whole houses, — Families were being led away from Christ in their entirety by these false teachers. Paul’s exhortation was for Titus to get a grasp on this situation before too much damage could be done. teaching things which they ought not, for filthy lucre's sake. —These false teachers were more interested in what they could get out of people than what they could give them.