Thomas Aquinas, on Ps 49:16

“But to the sinner God hath said: Why dost thou declare my justices, and take my covenant in thy mouth?”

“"But to the sinner God has said." Here he bars certain ones, namely sinners, from the sacrifice of praise; and he sets forth three things. First, human perversity. Second, God's patience. Third, he threatens divine severity. Human perversity consists in this, that they say good things and do evil; and therefore he shows how they are unworthy to speak good things. Now there is a twofold good: one is the instruction of morals, the other is formation for the praise of God. He says, therefore: you, namely my people, "offer to God the sacrifice of praise," etc. "But to the sinner God has said," that is, by God's preordination it is fixed that it is unjust for him to say good things and do evil. And he said this because it is impressed in the minds of all, even of sinners. And what did he say? "Why do you declare my justices?" Rom. 2: "You who preach not to steal, do you steal?" But does one who is in the state of mortal sin commit mortal sin when he preaches or teaches? It must be said that his sin is either public or hidden; and if hidden, it is either from contempt and without penance, or with penance. It must be said, therefore, that if someone is in public sin, he should not publicly preach or teach. And I say "public," because if the sin is not public, he could with charity privately admonish his brother concerning a sin even lesser than his own hidden sin, yet admonishing himself as well. But if he is in hidden sin and without penance, then he provokes God, because he simulates. Prov. 11: "The dissembler deceives his friend with his mouth." And it is of these that he speaks here, as the Gloss of Augustine says: "Let the tongue, which the conscience contradicts, not presume to praise." But if the sin is hidden and he grieves over it, he does not sin by preaching or teaching, even if he speaks publicly against that sin, because by detesting the sins of others he also detests his own. "And you take my covenant in your mouth." "Justice" refers to instruction; "covenant" refers to the praise of faith. Sir. 15: "Praise is not seemly in the mouth of a sinner," because the name of God is most holy; and therefore it is unfitting for it to be taken up by sinners, as if usurped. Prov. 26: "As a lame man has fine legs in vain, so a parable is unseemly in the mouth of fools."”

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