For even now, if believers choose to cheer themselves with musical instruments, they should, I think, make it their object not to dissever their cheerfulness from the praises of God. But when they frequent their sacred assemblies, musical instruments in celebrating the praises of God would be no more suitable than the burning of incense, the lighting up of lamps, and the restoration of the other shadows of the law. The Papists, therefore, have foolishly borrowed this, as well as many other things, from the Jews. Men who are fond of outward pomp may delight in that noise; but the simplicity which God recommends to us by the apostle is far more pleasing to him. Paul allows us to bless God in the public assembly of the saints only in a known tongue. The voice of man, although not understood by the generality, assuredly excels all inanimate instruments of music; and yet we see what St Paul determines concerning speaking in an unknown tongue. What shall we then say of chanting, which fills the ears with nothing but an empty sound? Does any one object, that music is very useful for awakening the minds of men and moving their hearts? I own it; but we should always take care that no corruption creep in, which might both defile the pure worship of God and involve men in superstition. Moreover, since the Holy Spirit expressly warns us of this danger by the mouth of Paul, to proceed beyond what we are there warranted by him is not only, I must say, unadvised zeal, but wicked and perverse obstinacy.
Calvin’s Lecture on Psalm 33:2