3 “Who can express the mighty acts of the Lord?”. Full of the consideration of the Divine works, while he entreats His mercy, “Who,” he says, “can express the mighty acts of the Lord, or make all His praises heard?” We must supply what was said above, to make the sense complete here, thus, “Who shall make all His praises heard?” that is, who is sufficient to make all His praises heard? “Shall make” them “heard,” he says; that is, cause that they be heard; showing, that the mighty acts of the Lord and His praises are so to be spoken of, that they may be preached to those who hear them.
But who can make “all,” heard? Is it that as the next words are, “Blessed are they that always keep judgment, and do righteousness in every time”; he perhaps meant those praises of His, which are understood as His works in His commandments? “For it is God,” says the Apostle, “who works in you,”...since He works in these things in a manner that cannot be spoken. “Who will do all His praises heard?” that is, who, when he has heard them, does all His praises? Which are the works of His commandments.
As far as they are done, although all which are heard are not performed, He is to be praised, who “works in us both to will and to do of His good pleasure.” For this reason, while he might have said, all His commandments, or, all the works of His commandments; he preferred saying, “His praises.”...
Source: The Enarrations, or Expositions, on the Psalms (New Advent)