Psalms 149:3

"Let them praise his name in the choir; let them play music for him on the timbrel and harp." In an earlier verse he said that we must rejoice in the Lord Christ, but now he says that we must praise the name of the Lord in the choir. That is to say, in the choir that never suffers any scattering, boredom or scandal, but is gathered in the uprightness of merits and always exists with the dearest unity. But another psalm explains what this choir is like and how big it is: "From the rising of the sun to its setting, praise the name of the Lord." The chorus that is gathered from the beginning of the world from the multitude of the heathen also cannot be gathered except in that heavenly homeland.

Let them praise his name in the choir. Wherever there is a choir, there diverse voices are gathered together into one song. For just as diverse strings produce the one sound of a song, so also diverse voices — that is, when they have been gathered together at once — make the choir of the Lord. Let them praise his name in the choir: where there is dissension, where there is envy, there is no choir. Let them praise his name in the choir: let them sing praise to him on the timbrel and the psaltery. Let this choir have a song, and have a timbrel and a psaltery. Let us crucify our bodies to Christ, and with such a timbrel let us sing to God. Let them sing praise to him on the timbrel and the psaltery. A timbrel does not have flesh, but a skin: and we, as long as we are fleshly, are not a timbrel. It is not a timbrel unless it has no flesh, unless it is stretched taut: a timbrel cannot be shrunken, but stretched out. And let sins not shrink us up, but let righteousness stretch us wide. Let us run through the rest. Let them sing praise to him on the timbrel and the psaltery. What we say in the choir, let us say this on the psaltery. The psaltery properly is a kind of musical instrument, which is like a lyre. It has a resemblance to a lyre, but it is not a lyre. Between the psaltery and the lyre there is this difference: the lyre is struck below, whereas the psaltery is struck above, which in the common word is called polyphthongon (many-toned). This, then, is the psaltery. Here, therefore, it is enjoined upon us that in the new song we should not sing to the Lord from below on the lyre, but from above, that is, on the psaltery.

"Let them praise His Name in chorus" [Psalm 149:3]. What means "chorus"? Many know what a "chorus" is: nay, as we are speaking in a town, almost all know. A "chorus" is the union of singers. If we sing "in chorus," let us sing in concord. If any one's voice is out of harmony in a chorus of singers, it offends the ear, and throwes the chorus into confusion. If the voice of one echoing discordantly troubles the harmony of them who sing, how does the discord of heresy throw into confusion the harmony of them who praise. The whole world is now the chorus of Christ. The chorus of Christ sounds harmoniously from east to west. "Let them sing a psalm unto Him with timbrel and psaltery." Wherefore takes he to him the "timbrel and psaltery"? That not the voice alone may praise, but the works too. When timbrel and psaltery are taken, the hands harmonize with the voice. So too do thou, whenever you sing, "Halleluia," deal forth your bread to the hungry, clothe the naked, take in the stranger: then does not only your voice sound, but your hand sounds in harmony with it, for your deeds agree with your words. You have taken to you an instrument, and your fingers agree with your tongue. Nor must we keep back the mystical meaning of the "timbrel and psaltery." On the timbrel leather is stretched, on the psaltery gut is stretched; on either instrument the flesh is crucified. How well did he "sing a psalm on timbrel and psaltery," who said, "the world is crucified unto me, and I unto the world"? [Galatians 6:14] This psaltery or timbrel He wishes you to take up, who loves a new song, who teaches you, saying to you, "Whosoever wills to be My disciple, let him deny himself, and take up his cross, and follow Me." [Matthew 16:24] Let him not set down his psaltery, let him not set down his timbrel, let him stretch himself out on the wood, and be dried from the lust of the flesh. The more the strings are stretched, the more sharply do they sound. The Apostle Paul then, in order that his psaltery might sound sharply, what said he? "Stretching forth unto those things which are before," etc. [Philippians 3:13] He stretched himself: Christ touched him; and the sweetness of truth sounded.