Samuel Barber — A last song

A last song, and a very last, and yet another O, when can I give over? Must I drive the pen until blood bursts from my nails And my breath fails and I shake with fever Or sit well wrapped in a many colored cloak Where the moon shines new through Castle Crystal? Shall I never hear her whisper softly: “But this is truth written by you only And for me only; Therefor, love, have done?”