3 Let us advert also to that sense, which concerning Christ our Lord Himself, our Head Himself, does present itself. For when Himself in form of a servant appeared on earth, they that crucified Him said, “He is not God.” Because Son of God He was, truly God He was. But they that are corrupted and have become abominable said what? “He is not God:” let us slay Him, “He is not God.” You have the voice of these very men in the book of Wisdom. For after there had gone before the verse, “The unwise man has said in his heart, There is no God;” as if reasons were required why the unwise man could say this, he has subjoined, “Corrupted they are, and abominable have become in their iniquities”. Hear ye those corrupted men. “For they have said with themselves, not rightly thinking:” corruption begins with evil belief, thence it proceeds to depraved morals, thence to the most flagrant iniquities, these are the grades. But what with themselves said they, thinking not rightly? “A small thing and with tediousness is our life.” From this evil belief follows that which also the Apostle has spoken of, “Let us eat and drink, for tomorrow we shall die.” But in the former passage more diffusely luxury itself is described: “Let us crown us with roses, before they be withered; in every place let us leave the tokens of our gladness.” After the more diffuse description of that luxury, what follows? “Let us slay the poor just man:” this is therefore saying, “He is not God.” Soft words they seemed but now to say: “Let us crown us with roses, before they be withered.” What more delicate, what more soft? Would you expect, out of this softness, Crosses, swords? Wonder not, soft are even the roots of brambles; if any one handle them, he is not pricked: but that wherewith you shall be pricked from thence has birth. “Corrupted,” therefore, are those men, “and abominable have become in their iniquities.” They say, “If Son of God He is, let Him come down from the Cross.” Behold them openly saying, “He is not God.”...
4. “The Lord from Heaven has looked forth upon the sons of men, that He might see if there is one understanding and seeking after God”. What is this? “Corrupted they are,” all these that say, “There is no God”? And what? Did it escape God, that they had become such? Or indeed to us would their inward thought be opened, except by Him it were told? If then He understood, if then He knew, what is this which has been said, “that He might see”? For the words are of one inquiring, of one not knowing. “God from Heaven has looked forth,” etc. And as though He had found what He sought by looking upon, and by looking down from Heaven, He gives sentence: “All men have gone aside, together useless they have become: there is not one that does good, not so much as one”. Two questions arise somewhat difficult: for if God looks out from Heaven, in order that He may see if there is one understanding or seeking after God; there steals upon an unwise man the thought, that God knows not all things. This is one question: what is the other? If there is not one that does good, is not so much as one; who is he that travails amid bad men? The former question then is solved as follows: ofttimes the Scripture speaks in such manner, that what by the gift of God a creature does, God is said to do....For hence has been said the following also, “For the Spirit searches all things, even the depth of God;” not because He that knows all things searches, but because to you has been given the Spirit, which makes you also to search: and that which by His own gift you do, He is said to do; because without Him you would not do it: therefore God is said to do, when you do. And because this by the gift of God you doest, God from heaven is “looking forth upon the sons of men.” The former question then, according to our measure, thus has been solved.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)