Forewarn (prolegw) --did forewarn (proeipon). Paul repeats his warning given while with them. He did his duty then. Gentile churches were peculiarly subject to these sins. But who is not in danger from them? Practise (prassonte). Prassw is the verb for habitual practice (our very word, in fact), not poiew for occasional doing. The habit of these sins is proof that one is not in the Kingdom of God and will not inherit it.