V. Once, indeed, the aged Simeon met the Saviour and received in his arms, as an infant, the Creator of the world, and proclaimed Him to be Lord and God; but now, in the place of foolish elders, children meet the Saviour, even as Simeon did, and instead of their arms, strew under Him the branches of trees, and bless the Lord God seated upon a colt, as upon the cherubim, Hosanna to the son of David: Blessed is He that comes in the name of the Lord; and together with these let us also exclaim, Blessed is He that comes, God the King of Glory, who, for our sakes, became poor, yet, in His own proper estate, being ignorant of poverty, that with His bounty He might make us rich. Blessed is He who once came in humility, and who will hereafter come again in glory: at the first, lowly, and seated upon an ass's colt, and by infants extolled in order that it might be fulfilled which was written: Your goings have been seen, O God; even the goings of my God, my King, in the sanctuary; but at the second time seated on the clouds, in terrible majesty, by angels and powers attended. O the mellifluous tongue of the children! O the sincere doctrine of those who are well pleasing to God! David in prophecy hid the spirit under the letter; children, opening their treasures, brought forth riches upon their tongues, and, in language full of grace, invited clearly all men to enjoy them. Therefore let us with them draw forth the unfading riches. In our bosoms insatiate, and in treasure-houses which cannot be filled, let us lay up the divine gifts. Let us exclaim without ceasing, Blessed is He that comes in the name of the Lord! Very God, in the name of the Very God, the Omnipotent from the Omnipotent, the Son in the name of the Father. The true King from the true King, whose kingdom, even as His who begot Him, is with eternity, coeval and pre-existent to it. For this is common to both; nor does the Scripture attribute this honour to the Son, as if it came from another source, nor as if it had a beginning, or could be added to or diminished— away with the thought!— but as that which is His of right by nature, and by a true and proper possession. For the kingdom of the Father, of the Son, and of the Holy Ghost, is one, even as their substance is one and their dominion one. Whence also, with one and the same adoration, we worship the one Deity in three Persons, subsisting without beginning, uncreate, without end, and to which there is no successor. For neither will the Father ever cease to be the Father, nor again the Son to be the Son and King, nor the Holy Ghost to be what in substance and personality He is. For nothing of the Trinity will suffer diminution, either in respect of eternity, or of communion, or of sovereignty. For not on that account is the Son of God called king, because for our sakes He was made man, and in the flesh cast down the tyrant that was against us, having, by taking this upon Him, obtained the victory over its cruel enemy, but because He is always Lord and God; therefore it is that now, both after His assumption of the flesh and for ever, He remains a king, even as He who begot Him. Speak not, O heretic, against the kingdom of Christ, lest you dishonour Him who begot Him. If you are faithful, in faith approach Christ, our very Cod, and not as using your liberty for a cloak of maliciousness. If you are a servant, with trembling be subject unto your Master; for he who fights against the Word is not a well-disposed servant, but a manifest enemy, as it is written: He that honours not the Son, honours not the Father which has sent Him.
VI. But let us, beloved, return in our discourse to that point whence we digressed, exclaiming, Blessed is He that comes in the name of the Lord: that good and kind Shepherd, voluntarily to lay down His life for His sheep. That just as hunters take by a sheep the wolves that devour sheep, even so the Chief Shepherd, offering Himself as man to the spiritual wolves and those who destroy the soul, may make His prey of the destroyers by means of that Adam who was once preyed on by them. Blessed is He that comes in the name of the Lord: God against the devil; not manifestly in His might, which cannot be looked on, but in the weakness of the flesh, to bind the strong man that is against us. Blessed is He that comes in the name of the Lord: the King against the tyrant; not with omnipotent power and wisdom, but with that which is accounted the foolishness of the cross, which has reft his spoils from the serpent who is wise in wickedness. Blessed is He that comes in the name of the Lord: the True One against the liar; the Saviour against the destroyer; the Prince of Peace against him who stirs up wars; the Lover of mankind against the hater of mankind. Blessed is He that comes in the name of the Lord: the Lord to have mercy upon the creature of His hands. Blessed is He that comes in the name of the Lord: the Lord to save man who had wandered in error; to put away error; to give light to those who are in darkness; to abolish the imposture of idols; in its place to bring in the saving knowledge of God; to sanctify the world; to drive away the abomination and misery of the worship of false gods. Blessed is He that comes in the name of the Lord: the one for the many; to deliver the poor out of the hands of them that are too strong for him, yea, the poor and needy from him that spoils him. Blessed is He that comes in the name of the Lord, to pour wine and oil upon him who had fallen among thieves, and had been passed by. Blessed is He that comes in the name of the Lord: to save us by Himself, as says the prophet; no ambassador, nor angel, but the Lord Himself saved us. Therefore we also bless You, O Lord; You with the Father and the Holy Spirit are blessed before the worlds and for ever. Before the world, indeed, and until now being devoid of body, but now and for ever henceforth possessed of that divine humanity which cannot be changed, and from which You are never divided.
Source: Oration on the Psalms (New Advent)