Churches of Christ do not sing a cappella because we dislike other kinds of music. Most of us have as many songs on iPods as the next person. We do not lack financial means to purchase instruments or capable musicians to play them. We are not just trying to be different or stubbornly upholding a longstanding tradition. Why, then, do we sing a cappella?
If we had the tongues of angels, we could not praise God as He deserves to be praised. If we were born speaking praises and had breath to never cease, we could never adequately exalt His name in this life. If every rock could speak, it would praise God. If the stars could sing, their song would be in His honor. If the animals could write, their words would form new praises for their Creator. The very stones would praise Him if the need arose, and a thousand legions of angels would leap to do His will.