The words of his mouth are iniquity and deceit: he has ceased to be wise, and to do good.
All Commentaries on Psalms 36:3 Go To Psalms 36
Augustine of Hippo
AD 430
3. "The words of his mouth are iniquity and deceit: he would not understand, that he might do good" (ver. 3). Ye see that he attributeth that to the will: for there are men who would understand and cannot, and there are men who would not understand, and therefore understand not. "He would not understand, that he might do good."