10 Observe then the “wonderful works” of God. “I have declared, and have spoken; they are multiplied beyond number.” There is “a number,” there are some over and above the number. There is a fixed number that belongs to that heavenly Jerusalem. For “the Lord knows them that are His;” the Christians that fear Him, the Christians that believe, the Christians that keep the commandments, that walk in God's ways, that keep themselves from sins; that if they fall confess: they belong to “the number.” But are they the only ones? There are also some “beyond the number.” For even if they be but a few (a few in comparison of the numbers of the larger majority), with how great numbers are our Churches filled, crowded up to the very walls; to what a degree do they annoy each other by the pressure, and almost choke each other by their overflowing numbers. Again, out of these very same persons, when there is a public spectacle, there are numbers flocking to the amphitheatre; these are over and above “the number.” But it is for this reason that we say this, that they may be in “the number.” Not being present, they do not hear this from us; but when you have gone from hence, let them hear it from you. “I have declared,” he says, “and have spoken.” It is Christ who speaks. “He has declared it,” in His own Person, as our Head. He has Himself declared it by His members. He Himself has sent those who should “declare” it; He Himself has sent the Apostles. “Their sound is gone out into all lands, and their words unto the ends of the world.” How great the number of believers that are gathered together; how great the multitudes that flock together; many of them truly converted, many but in appearance: and those who are truly converted are the minority; those who are so but in appearance are the majority: because “they are multiplied beyond the number.”
11....These are the “wonderful works” of God; these are the “thoughts” of God, to which “no man's thoughts are like;” that the lover of sight-seeing may be weaned from curiosity: and with us may seek after those more excellent, those more profitable things, in which, when he shall have attained unto them, he will rejoice....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)