Quotable

Error, indeed, is never set forth in its naked deformity, lest, being thus exposed, it should at once be detected. But it is craftily decked out in an attractive dress, so as, by its outward form, to make it appear to the inexperienced...more true than the truth itself. One far superior to me has well said..., “A clever imitation in glass casts contempt, as it were, on that precious jewel the emerald....” Lest, therefore, through my neglect, some should be carried off, even as sheep are by wolves, while they perceive not the true character of these men, because they outwardly are covered with sheep’s clothing (against whom the Lord has enjoined us to be on our guard), and because their language resembles ours, while their sentiments are very different.

—Irenaeus of Lyons, The Refutation and Overthrow of Knowledge Falsely So Called (Adversis Haereses-original Greek fragments), A.D. 180