13 But what he adds, “and those fettered in heart in wisdom;” other copies read, “instructed,” not “lettered:” the Greek verb, expressing both senses, only differing by a single syllable. But since these also, as it is said, put their “feet in the fetters” of wisdom, are taught wisdom (he means the feet of the heart, not of the body), and bound by its golden chains depart not from the path of God, and become not runaways from him; whichever reading we adopt, the truth in the meaning is safe. Them thus lettered, or instructed in heart in wisdom, God makes so well known in the New Testament, that they despised all things for the Faith which the impiety of Jews and Gentiles abhorred; and allowed themselves to be deprived of those things which in the Old Testament are thought high promises by those who judge after the flesh.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)