Thomas Aquinas, on Ps 13:3

“They are all gone aside, they are become unprofitable together: there is none that doth good, no not one. Their throat is an open sepulchre: with their tongues they acted deceitfully; the poison of asps is under their lips. Their mouth is full of cursing and bitterness; their feet are swift to shed blood. Destruction and unhappiness in their ways: and the way of peace they have not known: there is no fear of God before their eyes.”

“What will he find when he has searched here? The contrary: because "all have turned aside"; and he sets forth three things: namely, a turning away from God, useless action, and cessation from good. He says, therefore, "All have turned aside," namely from God: Deut. 31: "I know that after my death you will act wickedly, and will turn aside from the way which I have commanded you": Hos. 4: "There is no truth, no knowledge, no mercy of God in the land": Jer. 8: "No one speaks what is good; there is none who does penance for his sin." Likewise, from the fact that one turns away from God, he becomes useless: because that is useless which does not attain that for which it was made. But man was made to enjoy God: Wis. 4: "The manifold brood of the wicked shall be of no use." Hence he says, "Together they have become useless." Likewise, they cease from good, because "there is none who does good," etc. This has already been expounded.”

Imported from an open dataset — not yet checked against the printed edition.