Humani Generis Redemptionem §12

¹² Now since nothing except harm and discredit can be expected for the Church from such as these, Venerable Brethren, you must exercise the greatest care, so that, if you detect any one for his own glory or for gain, abusing the office of preaching, you should at once remove him from that function. For the man who does not scruple to defile so holy an office by such an unworthy perversion of its end, surely will not hesitate to descend to any indignity, and will bring the stain of ignominy not merely upon himself, but upon the sacred office also which he so unworthily administers.