12 These beasts, then, drink those waters, but passing; not staying, but passing; for all that teaching which in all this time is dispensed passes....Unless perchance your love thinks that in that city to which it is said, “Praise the Lord, O Jerusalem, praise your God, O Sion; for He has made strong the bars of your gates;” when the bars are now strengthened and the city closed, whence, as we said some time since, no friend goes out, no enemy enters; that there we shall have a book to read, or speech to be explained as it is now explained to you. Therefore is it now treated, that there it may be held fast: therefore is it now divided by syllables, that there it may be contemplated whole and entire. The Word of God will not be wanting there: but yet not by letters, not by sounds, not by books, not by a reader, not by an expositor. How then? As, “In the beginning was the Word,” etc. For He did not so come to us as to depart from thence; because He was in this world, and the world was made by Him. Such a Word are we to contemplate. For “the God of gods shall appear in Zion.” But this when? After our pilgrimage, when the journey is done: if however after our journey is done we be not delivered to the Judge, that the Judge may send us to prison. But if when our journey is ended, as we hope, and wish, and endeavour, we shall have reached our Country, there shall we contemplate What we shall ever praise; nor shall That fail which is present to us, nor we, who enjoy: nor shall he be cloyed that eats, nor shall that fail which he eats. Great and wonderful shall be that contemplation....
13. “The onagers shall take for their thirst.” By onagers he means some great beasts. For who knows not that wild asses are called onagers? He means, therefore, some great untrained ones. For the Gentiles had no yoke of the Law: many nations lived after their own customs, ranging in proud boastfulness as in a wilderness. And so indeed did all the beasts, but the wild asses are put to signify the greater sort. They too shall drink for their thirst, for for them too the waters flow. Thence drinks the hare, thence the wild ass: the hare little, the wild ass great; the hare timid, the wild ass fierce: either sort drinks thence, but each for his thirst....So faithfully and gently does it flow, as at once to satisfy the wild ass, and not to alarm the hare. The sound of Tully's voice rings out, Cicero is read, it is some book, it is a dialogue of his, whether his own, or Plato's, or by whatever such writer: some hear that are unlearned, weak ones of less mind; who dares to aspire to such a thing? It is a sound of water, and that perchance turbid, but certainly flowing so violently, that a timid animal dare not draw near and drink. To whom sounds a Psalm, and he says, It is too much for me? Behold now what the Psalm sounds; certainly they are hidden mysteries, yet so it sounds, that even children are delighted to hear, and the unlearned come to drink, and when filled burst forth in singing....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)