On the Making of Man by Gregory of Nyssa — Read

Now since our Maker has bestowed upon our formation a certain Godlike grace, by implanting in His image the likeness of His own excellences, for this reason He gave, of His bounty, His other good gifts to human nature; but mind and reason we cannot strictly say that He gave, but that He imparted them, adding to the image the proper adornment of His own nature. Now since the mind is a thing intelligible and incorporeal, its grace would have been incommunicable and isolated, if its motion were not manifested by some contrivance. For this cause there was still need of this instrumental organization, that it might, like a plectrum, touch the vocal organs and indicate by the quality of the notes struck, the motion within.

And as some skilled musician, who may have been deprived by some affection of his own voice, and yet wish to make his skill known, might make melody with voices of others, and publish his art by the aid of flutes or of the lyre, so also the human mind being a discoverer of all sorts of conceptions, seeing that it is unable, by the mere soul, to reveal to those who hear by bodily senses the motions of its understanding, touches, like some skilful composer, these animated instruments, and makes known its hidden thoughts by means of the sound produced upon them.