Hippolytus of Rome

David alone of the prophets prophesied with an instrument, called by the Greeks the "psaltery." … But this psaltery has the source of its musical numbers above, in order that we, too, may practice seeking things above and not suffer ourselves to be borne down by the pleasure of melody to the passions of the flesh. And I think that this truth, too, was signified deeply and clearly to us in a prophetic way in the construction of the instrument, namely, that those who have souls well ordered and trained have the way ready to things above. And again, an instrument having the source of its melodious sound in its upper parts may be taken as like the body of Christ and his saints—the only instrument that maintains rectitude; "for he did no sin, neither was guile found in his mouth." This is indeed an instrument, harmonious, melodious, well-ordered, that took in no human discord and did nothing out of measure but maintained in all things, as it were, harmony toward the Father; for, as he says, "he that is of the earth is earthly and speaks of the earth; he that comes from heaven testifies of what he has seen and heard."