The third poem from Rainer Maria Rilke's Sonnets to Orpheus struck me hard when I encountered it in Russell Burnham's setting for mixed chorus a few years back. For me, Rilke's poem is the ultimate distillation of what makes for truly great singing.
The analysis in the old Shambhala edition I used to have points out that the poem is written to Orpheus, who "is our inner poet. He is not singing pretty wish-fulfillments. He is singing the truth. ... He willingly steps into a mode of being in which all the ordinary human dichotomies are reconciled in an infinite wholeness."
Russell used a different translation; I prefer this one by Willis Barnstone. (Thanks to Mlle U- for digging out these quotes and this translation. Who knows where my copy disappeared to.) Rilke's original in German here.
Sonnets to Orpheus by Rainer Maria Rilke
A god can do it. But will you tell me how
a man can enter through the lyre's strings?
Our mind is split. And at the shadowed crossing
of heart-roads, there is no temple for Apollo.
Song, as you have taught it, is not desire,
not wooing any grace that can be achieved;
song is reality. Simple, for a god.
but when can WE be real? When does he pour
the earth, the stars, into us? Young man,
it is not your loving, even if your mouth
was forced wide open by your own voice -- learn
to forget that passionate music. It will end.
True singing is a different breath,
about nothing. A gust inside the god. A wind.
Gesang ist nicht Begehr; Gesang ist Dasein. How's that for a deep thought for the day?