24 We then are burdened by the sluggishness of this cold body, and the bonds of this earthly and corruptible life; have we no hope of receiving “the Word,” which “runs even unto swiftness”? Or has abandoned us, though by the body we are depressed to the lowest depths? Did not He predestinate us, before we were born in this mortal and sluggish body? He then, who predestinated us, gave snow to the earth, even ourselves. For now let us come to those somewhat obscure verses of the Psalm, let those entanglements begin to be unrolled. Behold, we are sluggish on this earth, and are as it were frozen here. And just as happens to the flakes of snow, for they freeze above, then fall down; so as love grows cold, human nature falls down to this earth, and involved in a sluggish body becomes like snow. But in that snow are predestined sons of God. For, “He gives snow like wool”. What is “like wool”? It means, of the snow which He has given, of these, who are as yet slow in spirit and cold, whom He has predestinated, He is about to make somewhat. For wool is the material of a garment: when we see wool, we look on it as a sort of preparation for a garment. Therefore since He has predestinated these, who at present are cold and creep on earth, and as yet glow not with the spirit of love (for as yet He speaks of predestination), God has given these as a sort of wool: He is about to make of them a garment. Rightly did the “raiment” of Christ “shine” on the mountain, “like snow.” The raiment of Christ did shine like snow, as though of that snow a garment had already been made: of which wool, that is, of the snow which He gave like wool, they being as yet predestined, were sluggish: but wait, see what follows. Since He gave them as wool, a garment is made of them. For as the Church is called the Body of Christ, so is the Church also called the garment of Christ: hence comes that which is said by the Apostle, “that He might present it to Himself a glorious Church, not having spot or wrinkle.” Let Him then present unto Himself a glorious Church, not having spot or wrinkle; let Him make Himself a garment of that wool, which He had predestinated in the snow. While men are yet unbelieving, and cold, and sluggish, let Him make a garment of this wool. That it may be washed from spots, let it be cleansed by faith: that it may have no wrinkle, let it be stretched out upon the cross....
25. “He scatters mist like ashes.” “He scatters,” says the Psalmist, “mist like ashes.” Who? He “who gives snow like wool.” For whom He predestined, He calls to repentance; for “whom He predestined, them He also called.” But “ashes” are connected with repentance. Hear Him calling to repentance, when He upbraided certain cities, saying, “Woe unto you, Chorazin! Woe unto you, Bethsaida! For if the mighty works which have been done in you had been done in Tyre and Sidon, they had long ago repented in dust and ashes.” Therefore, “He scatters mist like ashes.” What is, “He scatters mist like ashes”? When a man is called to learn about God, and it is said to him, “Receive the truth;” he begins to wish to receive the Truth, but is not able; he sees that He is under a sort of darkness, which before he saw not....Wander not in the mist, follow in faith. But forasmuch as you endeavour to see and art not able, repent of your sins, for mist is scattered like ashes. Repent you now of having been obstinate against God, repent of having followed your own evil ways. You have come into this state where it is difficult for you to see the vision of bliss, and the mist will be healthful to you, which God scatters like ashes. Thou yourself art as yet a mist, but like ashes. For they that are penitent, as yet roll themselves in ashes, my brethren, testifying, as it were, that they are like it, saying unto God, “I am ashes.” For a certain Scripture says, “I have despised myself, and wasted away, I have reckoned myself earth and ashes.” This is the humility of the penitent. When Abraham speaks to his God, and wishes the burning of Sodom to be disclosed to him, he says, “I am but earth and ashes.” How has this humility ever been found in great and holy men!
26. “Who sends His crystal like morsels of bread”. We need not spend our toil again in saying what crystal is. We have already said it, and I do not think that you, beloved, have forgotten it. What is then, “He sends His crystal like morsels of bread”? What is “crystal”? It is very hard, it is very tightly congealed; it can not, like snow, be easily melted. Snow, hardened by many years' duration, and by the succession of ages, is called “crystal,” and this “He sends like morsels of bread.” What means this? They were too hard, no longer fit to be compared to snow, but to crystal; but they too are predestinated and called, and some of them even so as to feed others, to be useful to others also. And what need is there to enumerate many, whom we happen to know, this one and that one? Every one when he thinks can recall to mind how hardened and obstinate some of those whom he knows have been, how they have struggled against the truth; yet now they preach the truth, they have been made morsels of bread. Who is that one Bread? “We being many,” says the Apostle, “are one Body in Christ;” he says also, “we being many are one Bread and one Body.” If then the whole Body of Christ is one Bread, the members of Christ are morsels of Bread. Of some that are hard He makes members of Himself, and useful for feeding others....Behold, the Apostle Paul was a crystal, hard, resisting the truth, crying out against the Gospel, hardening himself, as it were, against the sun....Since then he was crystal, he appeared clear and white, but he was hard and very cold. How was he bright and white? “An Hebrew of the Hebrews; as touching the law, a Pharisee.” Behold the brightness of crystal. Now hear the hardness of crystal. “As touching zeal, persecuting the Church” of Christ. Among the stoners of the holy martyr Stephen, was he, hard, perhaps harder than all. “For he kept the raiment of all who were stoning,” so that he stoned by the hands of all.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)