The active and passive purifications of the soul. Before reaching the light of perfect union, the soul passes through two nights, the night of sense and the night of the mind or spirit. The first is bitter, for the soul must deprive itself of all worldly pleasures, which is as night to the senses; it must have faith, like night to the intellect; God is incomprehensible and infinite and hence in this life is as night to the soul. The second caused much suffering, because the light and wisdom of contemplation is most pure, and clear, while the soul within which it shines is still imperfect and dark.