So many today put lyrics over harmony; they say that as long as the lyrics are wholesome, it does not matter how one composes the sound. It is on this idea that “Christian rap” and “Christian metal” were founded.
To those who think such things, tell me, was it not the sound of David’s harp that drove the demon who possessed Saul away? David did not sing, but play, and yet it was the very harmony of his composition that exorcised the evil spirit. Harmony, and the order of sound, does matter in music. God loves order, and hates disorder. He took the earth when it was in chaos, and brought it sequence and organization.
True music is as timeless as eternity, being composed within the finite world by mortal hands, yet first conceived in the infinite mind of God; it takes that which is “without form, and void” (Genesis 1:2), and engraves upon the human heart that very sublime concept of “In the beginning God created” (Genesis 1:1). The flesh is struck by a darkness that fills the waters of the soul and plunges our very beings to a chasm of emptiness, and it is true music that elates our minds with the words, “Let there be light” (Genesis 1:3). It is true music that, when it is done before the oppressed soul, repulses the devils away, scatters and drives them to the abyss, as what happened when David played the harp for King Saul, for “the light shineth in darkness; and the darkness comprehended it not.” (John 1:5)
Source:
http://shoebat.com/2014/08/28/satanic-christian-music-infiltrated-churches/