Augustine of Hippo

Let us sing, therefore, a new song, singing praise with a psaltery of ten strings. This is the new song, the grace of the New Testament, which distinguishes us from the old man, who was first made of the earth, earthly. For he was made from the clay, and having lost blessedness, he was justly cast into misery, because he had become a transgressor of the commandment. But what does the one who gives thanks to the grace of God through the forgiveness of sins, reconciling us to God and renewing the old things of the past, say in the words of the Prophet? He says, "He brought me out of the pit of misery and out of the mire of clay, and set my feet upon a rock, and directed my steps, and put a new song in my mouth, a hymn to our God." This is the new song, which is sung with a psaltery of ten strings. For no one praises God, that is, sings a hymn, unless he agrees with his mouth by his deeds, by loving God and neighbor. Nor should the rebaptizing Donatists think they belong to the new song. For they do not sing the new song, who, with arrogant impiety, have been cut off from the Church, which God wished to be in all the earth. For indeed, elsewhere the same Prophet says, "Sing to the Lord a new song, sing to the Lord, all the earth." Therefore, he who does not wish to sing with all the earth, staying with the old man, does not sing the new song, nor does he play on the psaltery of ten strings, because he is an enemy of charity, which is the fullness of the law, which we say is contained in the ten commandments pertaining to the love of God and neighbor.