As to public prayers, there are two kinds: the one consists of words alone; the other includes music. And this is no recent invention. For since the very beginning of the church it has been this way, as we may learn from history books. Nor does St. Paul himself speak only of prayer by word of mouth, but also of singing. And in truth, we know from experience that song has a great power and strength to move and inflame the hearts of men to invoke and praise God with a heart more vehement and ardent.