Augustine of Hippo

Our King in this Psalm speaks in the character of the human nature He assumed, of whom the royal title at the time of His passion was eminently set forth. Now He saith as follows; "Preserve me, O Lord, for in Thee have I hoped" (ver. 1): "I have said to the Lord, Thou art my God, for Thou requirest not my goods" (ver. 2): for with my goods Thou dost not look to be made blessed.

Exposition on Psalm 16 ↗

Jerome

An inscription of a title, to David himself. In place of this the fifth edition put the Hebrew word itself, "MACTHAM David," which Aquila translated as "of the humble and simple David," and Symmachus as "of the humble and unstained David." And Aquila himself again, in the fifty-fifth psalm and in the rest as far as the fifty-ninth, rendered this very thing so as to say "of the humble and perfect David." From this we understand that one word signifies both "simple" and "unstained" and "perfect," yet in such a way that humility is …

Homily 61, on Psalm 15 ↗

Thomas Aquinas

In the preceding Psalm he enumerated the just deeds that God requires of man; here, however, he shows how he followed justice. The title is this: "The inscription of the title of David himself." And according to the literal sense, it signifies that it was composed specifically about those things which pertain to the person of David. But because David also bore the person of Christ who was to be born from his seed, therefore certain things here are said of David, and certain things of Christ. …

Exposition on the Psalms of David ↗