4 Let us therefore “give thanks to the God of gods, and the Lord of lords, for His mercy,” etc. “Who alone did wonderful things”. As at the last part of every verse, it is written, “For His mercy endures for ever,” so we must understand at the beginning of each, though it be not written, “Give thanks.” Which indeed in the Greek is very plain. It would be so in Latin, if our translators had been able to make use of that expression. Which indeed they could have done in this verse, if they had said, “To Him who does wonderful things.”
For where we have, “who did wonderful things,” the Greek has τῷ ποιήσαντι, where we must necessarily understand, “give thanks.” And I would they had added the pronoun, and said to Him, “who did,” or to Him “who does,” or to Him “who made sure;” because then one might easily understand, “let us give thanks.” For now it is so obscurely rendered, that he who either knows not or cares not to examine a Greek manuscript may think, “who made the heavens, who made sure the earth, who made the luminaries, for His mercy endures for ever,” has been so said, because He did these things for this reason, “because His mercy endures for ever:” whereas they, whom He has freed from misery, belong to His Mercy: but not that we should believe that He makes sky, earth, and luminaries, of His Mercy; since they are marks of His Goodness, who created all things very good. For He created all things, that they might have their being; but it is the work of His Mercy, to cleanse us from our sins, and deliver us from everlasting misery.
And so the Psalm thus addresses us, “Give thanks unto the God of gods, give thanks unto the Lord of lords.” Give thanks to Him, “who alone does great wonders;” give thanks to Him, “who by His wisdom made the heavens;” give thanks to Him, “who stretched out the earth above the waters;” give thanks to Him, “who alone made great lights.” But why we are to praise, he sets down at the end of all the verses, “for His mercy endures for ever.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)