Time and space are the very music of God's harp, for each moment in time is empty of other moments, and each part of space is empty of other parts, so that we will not have to hear too much at once. That is why there are seasons.
The angels can know us more intimately and love us when we sing, and they are not asking that we sound like the Philharmonic. They ask us simply to sing because we are harmonic. We are symphonic and in these ways we can connect with the angelic world. I think and feel that the angels wait for us at every given moment. If we alternate song and silence, consciously, with burning attention, every rounded tone carves out the possibility to bridge heaven and earth, to live the material half of the angel.