The Nameless Quest in The Gate of the Sanctuary from The Temple of the Holy Ghost (Collected Works, Vol I) by Aleister Crowley.

“Yet the thought chilled me as I touched the reins.
Ah! the poor horse, he will not. So remains,
Divided in his love. With mastered tears
I stride toward the parapet. My ears
Catch his low call; and now a song complains.
The bridge is bleeding and the river hears.
Ah! God! I cannot live for pity deep
Of that heart-quelling chant—I could not sleep
Ever again to think of it. I close
My hearing with my fingers. Gently goes
A quivering foot above them as they weep—
I weep, I also, as the river flows.
Slowly the bridge subsides, and I am flung
Deep in the tears and terrors never sung.
I swim with sorrow bursting at my breast.
Yet I am cleansed, and find some little rest.
Still from my agonised unspeaking tongue
Breaks: I must go, go onward to the quest.” [via]