2 “For he has wrought deceitfully in His sight”. In whose sight? In His, whose fear was not before the eyes of him that did work deceitfully. “To find out his iniquity, and hate it.” He wrought so as not to find it. For there are men who as it were endeavour to seek out their iniquity, and fear to find it; because if they should find it, it is said to them, Depart from it: this you did before you knew; you did iniquity being in ignorance; God gives pardon: now you have discovered it, forsake it, that to your ignorance pardon may easily be given; and that with a clear face you may say to God, “Remember not the sins of my youth, and of my ignorance.” Thus he seeks it, thus he fears lest he find it; for he seeks it deceitfully.
When says a man, I knew not that it was sin? When he has seen that it is sin, and ceases to do the sin, which he did only because he was ignorant: such an one in truth would know his sin, to find it out, and hate it. But now many “work deceitfully to find out their iniquity:” they work not from their heart to find it out and hate it. But because in the very search after iniquity, there is deceit, in the finding it there will be defence of it. For when one has found his iniquity, lo now it is manifest to him that it is iniquity.
Do it not, you say. And he who wrought deceitfully to find it out, now he has found, hates it not; for what says he? How many do this! Who is there that does it not? And will God destroy them all? Or at least he says this: if God would not these things to be done, would men live who commit the same? Do you see that you worked deceitfully to find out your iniquity? For if not deceitfully but sincerely you had wrought, you would now have found it out, and hated it; now you have found it out, and you defend it; therefore you worked deceitfully, when you sought it.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)