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

“Yes, yes! let fancy sup
That grislier banquet than old Atreus9 planned!
Mind cannot fathom, nor the brain conceive,
Nor soul assimilate, nor heart believe
The horror of that Thing without a Name.
Full on me, boasting, like Death’s hand it came,
And struck me headlong.” [via]

Aleister Crowley notes on this text: 9. Atreus, King of Mycenae, gave a banquet of pretended reconciliation to his half-brother Thyestes, at which the two sons of Thyestes were served up.

Consider also:

  1. “The king did start, Gripped my strong hands, and held me to his heart, And could not speak a moment. Then he set A curb of sorrow and subdued its dart. ‘Go! and the blessing of high God attend Thy path, and lead thee to the doubtful end. No tongue that secret ever may reveal. Thy soul is god-like and thy frame is steel; Thou mayst win the quest–the king, thy friend, Gives thee his sword to keep thee–Gereth, kneel! ‘I dub thee Earl; arise!’ And then there rings The queen’s voice: ‘Shall my love not match the king’s? Here, from my finger drawn, this gem of power Shall guard thee in some unimagined hour. It hath strange virtue over mortal things. I freely give it for thy stirrup’s dower.’ I left the presence. Now the buffeting wind Gladdens my face–I leave the court behind. Am I Stark mad? My face grows grim and grave; I see–O Mary Mother, speak and save! I stare and stare until mine eyes are blind– There was no jewel in the ring she gave!”
  2. “Oh! my pure heart! Adulterous love began So subtly to identify the man With its own perfumed thoughts. So steals the grape Into the furtive brain–a spirit shape Kisses my spirit as no woman can. I love her–yes; and I have no escape. I never spoke, I never looked! But she Saw through the curtains of the soul of me, And loved me also! It is very well. I am well started on the road to Hell.”
  3. “The king was silent. None of us would stir. I sat, struck dumb, a living sepulchre. For–hear me! in my heart this thing became My sacrament, my pentecostal flame. And with it grew a fear–a fear of Her. What Her? Shame had not found itself a name. Simply I knew it in myself. I brood Ten years–so seemed it–O! the bitter food In my mouth nauseate! In the silent hall One might have heard God’s sparrow in its fall. But I was lost in mine own solitude– I should not hear Mikhael’s trumpet-call. Yet there did grow a clamour shrill and loud: One cursed, one crossed himself, another vowed His soul against the quest; the tumult ran Indecorous in that presence, man to man. Stilled suddenly, beholding how I bowed My soul in thought: another cry began. ‘Gereth the dauntless! Gereth of the Sea! Gereth the loyal! Child of royalty! witch-mothered Gereth! Sword above the strong, heart pure, head many-wiled!’ The knightly throng Clamour my name, and flattering words, to me– If they may ‘scape the quest–I do them wrong; They are my friends! Yet something terrible Rings in the manly music that they swell. They are all caught in this immense desire Deeper than heaven, tameless as the fire. All catch the fear–the fear of Her–as well, And dare not–even afraid, I must aspire.”
  4. “What meets mine ear, That every nerve and bone of me cries halt? What is this cold that nips me at the throat? This shiver in my blood? this icy note Of awe within my agonising brain? Neither of shame, nor love, nor fear, nor pain, Nor anything? Has love no antidote, Courage no buckler? Hark! it comes again. Friend, hast thou heard the wailing of the damned? Friend, hast thou listened when a murderer shammed Pale smiles amid his fellows as they spoke Low of his crime: his fear is like to choke His palsied throat. How, if Hell’s gate were slammed This very hour upon thy womanfolk? Conceive, I charge thee! Brace thy spirit up To drink at that imagination’s cup! Then, shriek, and pass! For thou shalt understand A little of the pressure of the hand That crushed me now.”
  5. “by a peculiar Ordinance of Heaven, and a Disposition occult within his Mind, is every Man protected from this Loss of his own Soul, until and unless he be by Choronzon disintegrated and dispersed beyond power of Will to repair; as when the Conflict within him, rending and burning, hath made his Mind utterly desert, and his Soul Madness.”