1....“Bless the Lord, O my soul.” Let the soul of us all, made one in Christ, say this. “O Lord my God, You are magnified exceedingly!”. Where are You magnified? “Confession and beauty You have put on.” Confess ye, that you may be beautified, that He may put you on. “Clothed with light as a garment”. Clothed with His Church, because she is made “light” in Him, who before was darkness in herself, as the apostle says: “You were sometime darkness, but now light in the Lord.” “Stretching out the heaven like a skin:” either as easily as thou dost a skin, if it be “as easily,” so that you may take it after the letter; or let us understand the authority of the Scriptures, spread out over the whole world, under the name of a skin; because mortality is signified in a skin, but all the authority of the Divine Scriptures was dispensed unto us through mortal men, whose fame is still spreading abroad now they are dead.
2. “Who covers with waters the upper parts thereof”. The upper parts of what? Of Heaven. What is Heaven? Figuratively only we said, the Divine Scripture. What are the upper parts of the Divine Scripture? The commandment of love, than which there is none more exalted. But wherefore is love compared to waters? Because “the love of God is shed abroad in our hearts by the Holy Spirit who is given unto us.” Whence is the Spirit Himself water? Because “Jesus stood and cried, He that believes in Me, out of his bosom shall flow rivers of living water.” Whence do we prove that it was said of the Spirit? Let the Evangelist himself declare, who follows it up, and says, “But this spoke He of the Spirit, which they were to receive, who should believe in Him.” “Who walks above the wings of the winds;” that is, above the virtues of souls. What is the virtue of a soul? Love itself. But how does He walk above it? Because the love of God toward us is greater than ours toward God.
3. “Who makes spirits His angels, and flaming fire His ministers”: that is, those who are already spirits, who are spiritual, not carnal, He makes His Angels, by sending them to preach His gospel. “And flaming fire His ministers.” For unless the minister that preaches be on fire, he enflames not him to whom he preaches.
4. “He has founded the earth upon its firmness”. He has founded the Church upon the firmness of the Church. What is the firmness of the Church, but the foundation of the Church. What is the foundation of the Church, but that of which the Apostle says, “Other foundation can no man lay but that is laid, which is Christ Jesus.” And therefore, grounded on such a foundation, what has she deserved to hear? “It shall not be bowed forever and ever.” “He founded the earth on its firmness.” That is, He has founded the Church upon Christ the foundation. The Church will totter if the foundation totter; but when shall Christ totter, before whose coming unto us, and taking flesh on Him, “all things were made by Him, and without Him was not anything made;” who holds all things by His Majesty, and us by His goodness? Since Christ fails not, “she shall not be bowed for ever and ever.” Where are they who say that the Church has perished from the world, when she cannot even be bowed....
5. “The deep, like a garment, is its clothing”. Whose? Is it perchance God's? But he had already said of His clothing, “Clothed with light as with a garment.” I hear of God clothed in light, and that light, if we will, are we. What is, if we will? If we are no longer darkness. Therefore if God is clothed with light, whose clothing, again, is the deep? For an immense mass of waters is called the deep. All water, all the moist nature, and the substance everywhere shed abroad through the seas, and rivers, and hidden caves, is all together called by one name, the Deep. Therefore we understand the earth, of which he said, “He has founded the earth.” Of it I believe he said, “The deep, like a garment is its clothing.” For the water is as it were the clothing of the earth, surrounding it and covering it....
6. “Above the mountains the waters shall stand:” that is, the clothing of the earth, which is the deep, so increased, that the waters stood even above the mountains. We read of this taking place in the deluge....The Prophet minding to foretell future things, not to relate the past, therefore said it, because he would have it understood that the Church should be in a deluge of persecutions. For there was a time when the floods of persecutors had covered God's earth, God's Church, and had so covered it, that not even those great ones appeared, who are the mountains. For when they fled everywhere, how did they but cease to appear? And perchance of those waters is that saying, “Save me, O God, for the waters have come in even unto my soul.” Especially the waters which make the sea, stormy, unfruitful. For whatsoever earth the sea-water may have covered, it will not rather make it fruitful than bring it to barrenness. For there were also mountains beneath the waters, because above the mountains waters stood....Why were the Apostles hidden by flight? Because “above the mountains the waters stood.” The power of the waters was great, but how long? Hear what follows.
7. “From Your rebuke they shall fly”. And this was done, brethren; from God's rebuke the waters did fly; that is, they went back from pressing on the mountains. Now the mountains themselves stand forth, Peter and Paul: how do they tower! They who before were pressed down by persecutors, now are venerated by emperors. For the waters are fled from the rebuke of God; because “the heart of kings is in the hand of God, He has bent it whither He would;” He commanded peace to be given by them to the Christians; the authority of the Apostles sprang up and towered high....The waters fled from the rebuke of God. “From the voice of Your thunder they shall be afraid.” Now who is there that would not be afraid, from the voice of God through the Apostles, the voice of God through the Scriptures, through His clouds? The sea is quieted, the waters have been made afraid, the mountains have been laid bare, the emperor has given the order. But who would have given the order, unless God had thundered? Because God willed, they commanded, and it was done. Therefore let no one of men arrogate anything to himself.
8. “The mountains ascend, and the plains go down, into the place which You have founded for them”. He is still speaking of waters. Let us not here understand mountains as of earth; nor plains, as of earth: but waves so great that they may be compared to mountains. The sea did sometime toss, and its waves were as mountains, which could cover those mountains the Apostles. But how long do the mountains ascend and the plains go down? They raged, and they are appeased. When they raged they were mountains: now they are appeased they have become plains: for He has founded a place for them. There is a certain channel, as it were a deep place, into which all those lately raging hearts of mortals have retired....They were mountains formerly, now they are plains: yet, my brethren, even a dead calm is sea. For wherefore are they not now violent? Wherefore do they not rage? Wherefore do they not try, if they cannot overthrow our earth, at least to cover it? Wherefore not?
Source: The Enarrations, or Expositions, on the Psalms (New Advent)