Let us speak of the good of psalmody, which God deigns to grant us. We therefore, beloved, who are all instructed by the teachings prophetic as well as evangelical and apostolic—whose words and deeds let us set before our eyes, through whom we are all that we are—and how pleasing and acceptable to God are spiritual songs, let us, repeating from the beginning, affirm by those same authors. But if we ask who first of all introduced this kind, we find none other than Moses, who bore an illustrious song to God, when, Egypt having been struck with ten plagues, and Pharaoh drowned, the people went out rejoicing through the unaccustomed paths of the sea to the desert, saying: Let us sing to the Lord; for he is gloriously honoured (Exod. 15:1).
First, therefore, Moses, leader of the tribes of Israel, established choirs, and taught both sexes in distinct ranks, himself and his sister leading, to sing the triumphal song to the Lord. Afterward Deborah, a noble woman in the book of Judges, is found to have performed this ministry. Yet Moses himself, about to depart from the body, repeated a terrifying song in Deuteronomy; which he left in writing to the people in place of a testament, that from it they might know what punishment and what tribulations would follow them, if they should depart from the Lord. Wretched all and pitiable, who, this so evident a denunciation being disregarded, would not beware of sins and of unlawful superstitions.
But indeed afterward you will find many, not only men, but also women, filled with the divine Spirit, to have sung the mysteries of God, even before David, who, from his boyhood specially chosen by the Lord for this office, deserved to be the chief of singers and the treasury of songs. He, while yet a boy, singing on the harp sweetly and bravely, restrained the malignant spirit that was working in Saul: not that there was such power in that harp, but because the figure of Christ's cross, which was mystically borne in the wood and the stretching of the strings, even then suppressed the spirit of the demon. What will you not find in these Psalms that may serve for the usefulness and edification, for the consolation of the human race, of every condition, sex, and age?
In the Psalms the infant has what to suck, the boy what to praise, the youth what to correct his way, the young man what to follow, the elder what to entreat. The woman learns chastity, orphans find a father, widows a judge, the poor a guardian, strangers a keeper; kings and judges hear what they should fear. The Psalm consoles the sad, tempers the joyful, mitigates the angry, refreshes the poor, admonishes the rich that they may know themselves, and rebukes them lest they be proud; to all without exception who take it up the Psalm imparts a fitting medicine; nor does it despise sinners, but wholesomely brings to them a remedy through tearful penitence.
Therefore the Lord our God, through David his servant, compounded a potion, which would be sweet to the taste through its chanting, and effectual to heal the wounds of sinners through its virtue. For the Psalm is sweetly heard while it is sung; it penetrates the soul while it delights; the Psalms are easily retained in memory, if they be frequently sung; and what the austerity of the Law could not wrest from human minds, these things exclude through the sweetness of song. For whatever the Prophets, whatever the Gospels themselves enjoin, is contained in these songs with the sweet delight of those who meditate.
God is shown forth that he may be feared, idols are laughed to scorn, justice is instilled, iniquity is forbidden, mercy is praised, unbelief is renounced, truth is sought, lies are condemned, deceit is accused, innocence is commended, pride is cast down, humility is exalted, penitence is preached, peace is set forth as to be pursued. Protection against enemies is besought, vengeance is promised, sure hope is nourished; and what is more excellent than all these, in the Psalms the sacraments of Christ are sung.
For both his generation is expressed, and the rejection of the impious people, and the inheritance of the nations is named, the Lord's mighty works are sung, the venerable Passion is depicted, the glorious Resurrection is shown, the seat also at the right hand is wondrously depicted. Then the Lord's fiery coming is made manifest, the terrible judgment of the living and the dead is laid open. What more? Even the sending forth of the creating Spirit, and the renewal of the earth, is revealed: after which there shall be in the glory of the Lord the everlasting kingdom of the just, and the perpetual punishment of sinners.