Thomas Aquinas, on Ps 19:1

“Unto the end. A psalm for David.”

“In the preceding Psalms he treated of liberation from persecution and gave thanks for the liberation; here, however, having been liberated, or standing in hope of liberation, he asks to be promoted to greater things. This Psalm, therefore, is divided into two parts. In the first part, a petition for exaltation is set forth. In the second, a promise is proposed, at "O Lord, in your strength," etc. Concerning the first, he does three things. First the petition is set forth. Second, the hope of being heard is set forth, at "Now I know." Third, the conclusion of the Psalm is set forth, at "O Lord, save," etc. Concerning the first, he does two things. First, a petition concerning evils is set forth. Second, concerning promotion to good, at "May he repay you." This Psalm proceeds in a different way from the preceding ones. In the other Psalms David is introduced praying for himself as one who asks; here he is introduced as though it were the prayer of others for him: and although according to the literal sense the things said here are in some way referred to David, yet they properly and truly pertain to Christ. According to the mystical sense, however, they pertain to the Church and to the just man: and in whatever way they are understood, concerning this part the Psalm does two things. First, the hearing of the one who prays is set forth. Second, the reason for the hearing is set forth, at "May he protect you." He says, therefore: O David, or O Christ, "may the Lord hear you"; 1 Mac. 1: "May he hear your prayers," etc. "May the Lord hear you." David suffered tribulations, and Christ likewise in his Passion: and therefore he says, "in the day of tribulation and rebuke": Is. 37: "This is a day of tribulation and rebuke and blasphemy." And in this, Christ was heard for himself and for others: Heb. 5: "In the days of his flesh, offering up with a strong cry and tears, he was heard." And the just man says: "When I was in trouble, I cried out, and he heard me." There is, therefore, a threefold cause that makes prayer worthy of being heard. The first is divine goodness. The second is the intercession of the saints. The third is one's own merit; because, as is said in Jn. 9, "God does not hear sinners; but if anyone is a worshiper of God, him he hears." The reason for the hearing is set forth when he says, "May the name of the God of Jacob protect you." The first cause: that is, on account of his name, that is, on account of his goodness. "May he protect you," if it is referred to Christ. But if it pertains to others, it is set forth thus: "May the name of the God of Jacob protect you" who pray. The God whom he himself worshiped when he appeared to him at Bethel: Gen. 28: the God of Jacob, who leads earthly ones to heaven, and from heaven assists the earthly. He, therefore, "may he protect you": Prov. 18: "The name of the Lord is a most strong tower": Ps. 30: "You shall protect them in your tabernacle," etc. This name is "Almighty": Ex. 15: "Who is able to save," etc. It is also a name of mercy: Lk. 1: "Holy," that is, merciful, "is his name": Song 1: "Your name is oil poured out." Thus, therefore, by the power and mercy of God we are protected: Is. 49: "In the shadow of his hand he has protected me": Ps. 16: "Under the shadow of your wings protect me."”

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