… and Zarathustra again alone … heard behind him a new voice which called out: “Stay! Zarathustra! Do wait! It is myself, O Zarathustra, myself, your shadow!” But Zarathustra did not wait … “Where has my lonesomeness gone?” spoke he.
My shadow calls me? What matter about my shadow! Let it run after me! I- run away from it.”
Thus spoke Zarathustra to his heart and ran away. But the one behind followed after him … (Nietzsche’s ‘Thus Spoke Zarathustra’ – LXIX).

The struggle against is as valiant as the struggle for; the difference lies in the fact that the one who struggles against has his back to the light. He is fighting his own shadow. It is only when this shadow exhausts him, when finally he falls prostrate, that the light which sweeps over him can reveal to him the splendours which he had mistaken for phantoms.
From Henry Miller’s ‘The Time of the Assassins’ (1946)