7 “Who gives food to the hungry.” Behold, from you I look for nothing: “God gives food to the hungry.” Who are “the hungry”? All. What is, all? To all things that have life, to all men He gives food: does He not reserve some food for His beloved? If they have another kind of hunger, they have also another kind of food. Let us first enquire what their hunger is, and then we shall find their food. “Blessed are they that hunger and thirst after righteousness, for they shall be filled.” We ought to be God's hungry ones....“The Lord looses them that are fettered; the Lord lifts up them that are dashed down; the Lord makes wise them that are blind”.
Perfectly has he by this last sentence explained to us all the preceding ones: lest perchance, when he had said, “the Lord looses them that are fettered,” we should refer it to those fettered ones, who for some crime are bound in irons by their masters: and in that he said, “He lifts up them that are dashed down,” there should occur to our minds some one stumbling or falling, or thrown from a horse. There is another kind of fall, there are other kinds of fetters, just as there is other darkness and other light.
Whereas he said, “He makes the blind wise;” he would not say, He enlightened the blind, lest you should understand this also in reference to the flesh, as the man was enlightened by the Lord, when He anointed his eyes with clay made with spittle, and so healed him: that you might not look for anything of this sort, when He is speaking of spiritual things, he points to a sort of light of wisdom, wherewith the blind are enlightened. Therefore in the same way as the blind are enlightened with the light of wisdom, so are the fettered set free, and those who are dashed down are lifted up.
Whereby then have we been fettered? Whereby dashed down? Our body was once an ornament to us: now, we have sinned, and thereby have had fetters put on us. What are our fetters? Our mortality....“The Lord loves the righteous.” And who are the “righteous”? How far are they righteous now? Just as you have; “the Lord, guards proselytes”. “Proselytes” are strangers. Every Church of the Gentiles is a stranger. For it comes in to the Fathers, not sprung of their flesh, but their daughter by imitating them.
Yet the Lord, not any man, guards them. “The orphan and widow He will take up.” Let none think that He takes up the orphan for his inheritance, or the widow for any business of hers. True, God does help them; and in all the duties of the human race, he does a good work, who takes care of an orphan, who abandons not a widow: but in a certain way we are all orphans, not because our Father is dead, but because He is absent....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)