Vespers for the Voiceless

If I were to commission a stained-glass window for my Church,
It would be a single Nightingale upon a beech branch in springtime.
Her tongueless trills would be the Hymns we would sing at sundown—
No noticeable pattern, only an algorithm inherited from the Ancients.

Our Priestess wears her sandy plumage as a sacred vestment,
Her legitimate lineage endows her with the power to Pardon.
Her mutilated blessings would help us to forgive our Tereusian Trespassers,
And dare her Congregation to turn laments into Praise.