9 But as His good works profited only the predestined to eternal salvation, and not all men, nor even all those among whom they were done, he adds, “Do you show wonders among the dead?”. If we suppose this relates to those whose flesh life has left, great wonders have been wrought among the dead, inasmuch as some of them have revived: and in our Lord's descent into Hell, and His ascent as the conqueror of death, a great wonder was wrought among the dead. He refers then in these words, “Do You show wonders among the dead?” to men so dead in heart, that such great works of Christ could not rouse them to the life of faith: for he does not say that wonders are not shown to them because they see them not, but because they do not profit them. For, as he says in this passage, “the whole day have I stretched forth My hands to You:” because He ever refers all His works to the will of His Father, constantly declaring that He came to fulfil His Father's will: so also, as an unbelieving people saw the same works, another Prophet says, “I have spread out my hands all day unto a rebellious people, that believes not, but contradicts.” Those then are dead, to whom wonders have not been shown, not because they saw them not, but since they lived not again through them. The following verse, “Shall physicians revive them, and shall they praise You?” means, that the dead shall not be revived by such means, that they may praise You. In the Hebrew there is said to be a different expression: giants being used where physicians are here: but the Septuagint translators, whose authority is such that they may deservedly be said to have interpreted by the inspiration of the Spirit of God owing to their wonderful agreement, conclude, not by mistake, but taking occasion from the resemblance in sound between the Hebrew words expressing these two senses, that the use of the word is an indication of the sense in which the word giants is meant to be taken. For if you suppose the proud meant by giants, of whom the Apostle says, “Where is the wise? Where is the scribe? Where is the disputer of this world?” there is no incongruity in calling them physicians, as if by their own unaided skill they promised the salvation of souls: against whom it is said, “Of the Lord is safety.” But if we take the word giant in a good sense, as it is said of our Lord, “He rejoices as a giant to run his course;” that is Giant of giants, chief among the greatest and strongest, who in His Church excel in spiritual strength. Just as He is the Mountain of mountains; as it is written, “And it shall come to pass in the last days, that the mountain of the Lord's house shall be manifested in the top of the mountains:” and the Saint of saints: there is no absurdity in styling these same great and mighty men physicians. Whence says the Apostle, “if by any means I may provoke to emulation them which are my flesh, and might save some of them.” But even such physicians, even though they cure not by their own power (as not even of their own do those of the body), yet so far forth as by faithful ministry they assist towards salvation, can cure the living, but not raise the dead: of whom it is said, “Do You show wonders among the dead?” For the grace of God, by which men's minds in a certain manner are brought to live a fresh life, so as to be able to hear the lessons of salvation from any of its ministers whatever, is most hidden and mysterious. This grace is thus spoken of in the Gospel. “No man can come to Me, except the Father which has sent Me draw him;”...in order to show, that the very faith by which the soul believes, and springs into fresh life from the death of its former affections, is given us by God. Whatever exertions, then, the best preachers of the word, and persuaders of the truth through miracles, may make with men, just like great physicians: yet if they are dead, and through Your grace have not a second life, “Do You show wonders among the dead, or shall physicians raise them? And shall they” whom they raise “praise You”? For this confession declares that they live: not, as it is written elsewhere, “Thanksgiving perishes from the dead, as from one that is not.”
10. “Shall one show Your loving-kindness in the grave, or Your faithfulness in destruction?”. The word “show” is of course understood as if repeated, Shall any show Your faithfulness in destruction? Scripture loves to connect loving-kindness and faithfulness, especially in the Psalms. “Destruction” also is a repetition of “the grave,” and signifies them who are in the grave, styled above “the dead,” in the verse, “Do you show wonders among the dead?” for the body is the grave of the dead soul; whence our Lord's words in the Gospel, “You are like whited sepulchres, which indeed appear beautiful outward, but within are full of dead men's bones, and of all uncleanness. Even so ye outwardly appear righteous unto men, but within you are full of hypocrisy and iniquity.”
11. “Shall your wondrous works be known in the dark, and your righteousness in the land where all things are forgotten?”, the dark answers to the land of forgetfulness: for the unbelieving are meant by the dark, as the Apostle says, “For you were sometimes darkness;” and the land where all things are forgotten, is the man who has forgotten God; for the unbelieving soul can arrive at darkness so intense, “that the fool says in his heart, There is no God.” Thus the meaning of the whole passage may thus be drawn out in its connection: “Lord, I have called upon You,” amid My sufferings; “all day I have stretched forth my hands unto You”. I have never ceased to stretch forth My works to glorify You. Why then do the wicked rage against Me, unless because “Thou showest not wonders among the dead”? Because those wonders move them not to faith, nor can physicians restore them to life that they may praise You, because Your hidden grace works not in them to draw them unto believing: because no man comes unto Me, but whom You have drawn. Shall then “Your loving-kindness be showed in the grave”? That is, the grave of the dead soul, which lies dead beneath the body's weight: “or Your faithfulness in destruction”? That is, in such a death as cannot believe or feel any of these things. “For how then in the darkness” of this death, that is, in the man who in forgetting You has lost the light of his life, “shall Your wondrous works and Your righteousness be known.”...
Source: The Enarrations, or Expositions, on the Psalms (New Advent)