From a discourse on the psalms by Saint Augustine, bishop (Ps. 32, sermo 1, 7-8: CCL 38, 253-254)
Blanchard, Jacques - Saint Cecilia
Praise the Lord with the lyre, make melody to him with the harp of ten strings! Sing to him a new song. Rid yourself of what is old and worn out, for you know a new song. A new man, a new covenant—a new song. This new song does not belong to the old man. Only the new man learns it: the man restored from his fallen condition through the grace of God, and now sharing in the new covenant, that is, the kingdom of heaven. To it all our love now aspires and sings a new song. Let us sing a new song not with our lips but with our lives.
Sing to him a new song, sing to him with joyful melody. Every one of us tries to discover how to sing to God. You must sing to him, but you must sing well. He does not want your voice to come harshly to his ears, so sing well, brothers!
If you were asked, “Sing to please this musician,” you would not like to do so without having taken some instruction in music, because you would not like to offend an expert in the art. An untrained listener does not notice the faults a musician would point out to you. Who, then, will offer to sing well for God, the great artist whose discrimination is faultless, whose attention is on the minutest detail, whose ear nothing escapes? When will you be able to offer him a perfect performance that you will in no way displease such a supremely discerning listener?
See how he himself provides you with a way of singing. Do not search for words, as if you could find a lyric which would give God pleasure. Sing to him “with songs of joy.” This is singing well to God, just singing with songs of joy.
But how is this done? You must first understand that words cannot express the things that are sung by the heart. Take the case of people singing while harvesting in the fields or in the vineyards or when any other strenuous work is in progress. Although they begin by giving expression to their happiness in sung words, yet shortly there is a change. As if so happy that words can no longer express what they feel, they discard the restricting syllables. They burst out into a simple sound of joy, of jubilation. Such a cry of joy is a sound signifying that the heart is bringing to birth what it cannot utter in words.
Now, who is more worthy of such a cry of jubilation than God himself, whom all words fail to describe? If words will not serve, and yet you must not remain silent, what else can you do but cry out for joy? Your heart must rejoice beyond words, soaring into an immensity of gladness, unrestrained by syllabic bonds. Sing to him with jubilation.