Sacred Music as Occasion of Grace for Modern Man

"The soul is distracted from that which is sung by a chant that is employed for the purpose of giving pleasure [only]. But if the singer chant for the sake of devotion, he pays more attention to what he says, both because he lingers more thereon, and because, as Augustine remarks, “each affection of our spirit, according to its variety, has its own appropriate measure in the voice, and singing, by some hidden correspondence wherewith it is stirred.” The same applies to the hearers, for even if some of them understand not what is sung, yet they understand why it is sung, namely, for God’s glory: and this is enough to arouse their devotion.The soul is distracted from that which is sung by a chant that is employed for the purpose of giving pleasure [only]. But if the singer chant for the sake of devotion, he pays more attention to what he says, both because he lingers more thereon, and because, as Augustine remarks, “each affection of our spirit, according to its variety, has its own appropriate measure in the voice, and singing, by some hidden correspondence wherewith it is stirred.” The same applies to the hearers, for even if some of them understand not what is sung, yet they understand why it is sung, namely, for God’s glory: and this is enough to arouse their devotion."

- St. Thomas Aquinas

Quoted in a wonderful article by Peter Kwasniewsky at OnePeterFive [LINK].