26 “Your mouth has abounded in malice, and your tongue has embraced deceit”. Of the malevolence and deceit, brethren, of certain men he speaks, who by adulation, though they know what they hear to be evil, yet lest they offend those from whom they hear, not only by not reproving but by holding their peace do consent. Too little is it, that they do not say, You have done evil: but they even say, You have done even well: and they know it to be evil: but their mouth abounds in malice, and their tongue embraces deceit.
Deceit is a sort of guile in words, of uttering one thing, thinking another. He says not, your tongue has committed deceit or perpetrated deceit, but in order to point out to you a kind of pleasure taken in the very evil doing, He has said, “Hath embraced.” It is too little that you do it, you are delighted too; you praise openly, you laugh to yourself. Thou dost push to destruction a man heedlessly putting forth his faults, and knowing not whether they be faults: thou that know it to be a fault, sayest not, “Whither are you rushing?”
If you were to see him heedlessly walk in the dark, where you knew a well to be, and were to hold your peace, of what sort would you be? Would you not be set down for an enemy of his life? And yet if he were to fall into a well, not in soul but in body he would die. He does fall headlong into his vices, he does expose before you his evil doings: you know them to be evil, and praisest and laughest to yourself. Oh that at length he were to be turned to God at whom you laugh, and whom you would not reprove, and that he were to say, “Let them be confounded that say to me, Well, well.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)