Mansur al-Hallaj, the Sufi mystic, who had attained communion with God by delving deep into the innermost recesses of his being through intense meditation, would say: "You can break a temple, you can break a mosque, but you must never break the human heart, because the heart is the very dwelling place of the Lord".
Pointing to his heart, he would say: 'Maa Fil Jubbati Illa-Allah' - There is nothing inside the cloak but God.
The Self is encased not merely in one but four bodies: physical, astral, causal and supra-causal. The four states of consciousness corresponding to the four bodies are: waking, dream, deep sleep and transcendental respectively.
In the initial stages of meditation, the physical body appears as a red light that envelops the seeker like a flame of fire or jyoti . As the seeker progresses in meditation, he passes from the physical to the astral body which manifests itself as a white, thumb-sized light of great brilliance. The dream state of consciousness is experienced through the astral body.
The seeker then experiences the black light of the size of a finger tip that corresponds to the causal body. The deep sleep state of consciousness is experienced through this body. This state is referred to as the state of total darkness, the state of void, where one is completely unaware of one's existence.
It is important for the spiritual aspirant to remain steadfast in his practice of meditation and to have unflinching faith in the Divine Power. This ultimately leads the seeker to the sublime state of turiya, in which the supra-causal body is experienced. In this state the seeker attains communion with God who manifests Himself in the form of the dazzling Blue Effulgence, called the Eternal Blue of Consciousness. The ego gets completely merged in the Divine Effulgence and all the past karmas of the seeker are burnt in the fire of atma-jnana .
Realisation then dawns upon the seeker that the universes that appear in the waking and dream states are phenomena upon the substratum of the Self, God which is not affected by these in any way. In the words of Ramana Maharshi: "The world is perceived as an apparent objective reality when the mind is externalised, thereby abandoning its identity with the Self. When the world is thus perceived the true nature of the Self is not revealed; conversely, when the Self is realised, the world ceases to appear as an objective reality".
A realised person sees the entire world as a blissful play of the Self where the knower, the known and the process of knowing merge together and become one. Sheikh Abdul Qadir Jilani, popularly known in India as Bare Pir or Great Guide, said: "The essence of life of realisation and contentment or faqr is this: a man does not need the world, the real wealth consists of having no desire for it". Despite being devoid of material prosperity, Mansur al-Hallaj enjoyed perfect equanimity as he had gained access to the vast inner, spiritual kingdom by restraining the fickleness of mind. Experiencing oneness with the Supreme Divinity, he would spontaneously utter the words "Ana'l haqq" ^ I am the Truth ^ in a state of spiritual ecstasy.
It is said that even after he was publicly crucified for taking the liberty of expressing his oneness with God, his mortal remains continued to utter these holy words.
From the writer's Sufi Cults and the Evolution of Mediaeval Indian Culture.