'Sing to God a new song, sing to him with joyful melody.' Each of us tries to discover how best to sing to God. We must sing to God, but we must sing well. God does not want his ears assaulted by our discordant voices. So sing well, my brothers and sisters, sing well!
If you were asked: 'Sing to please this musician,' you would not dare to do so without first having had some music lessons, because you would not want to offend such an expert in the art. An undiscerning listener does not notice the faults that an accomplished musician would point out to you. Who, then, offer to sing well for God, the great artist whose discrimination is faultless, whose attention notices the minutest detail, whose ear nothing escapes? When will you be able to offer him a perfect performance so that you will in no way displease such a supremely discerning listener?
Augustine goes on to tell us that in fact we should be bursting out with joyful song like harvesters in the fields, and I can't help feeling that this is a somewhat naive picture - can't help thinking of all these sore backs and aching muscles and the harvesters too exhausted to sing. But there are days when I think of poor God with his fingers in his ears.
Cosmically speaking, of course.