"809 Dz 434 Because some indeed "under the pretext of piety, denying his power" (according to what the Apostle says) (2Tm 3,5), assume to themselves the authority of preaching, when the same Apostle says: "How . . . shall they preach, unless they are sent?" (Rm 10,15), let all who, being prohibited or not sent, without having received authority from the Apostolic See, or from the Catholic bishop of the place, shall presume publicly or privately to usurp the duty of preaching * be marked by the bond of excommunication; and unless they recover their senses, the sooner the better, let them be punished with another fitting penalty."
809 Denzinger 434, The necessity of a canonical mission, Chap. 3 . (Condemnation of) The Heretics £[Waldensian]*