Imam in his famous work of "Combat with the self explains the matter as follwoing:
Attention to other than God covers man with veils of darkness and light.
If any worldly affair is a cause for man’s attention to be directed toward the world and to neglect God, the Exalted, it raises dark veils.
All of the corporeal worlds are dark veils.
If the world is a means of directing attention to the Truth and for arriving at the abode of the Hereafter, which is the “abode of honor,” then the dark veils are transformed into veils of light, Imam Khomeini further explains.
“Being perfectly cut off from all else” means tearing and pushing aside all the dark and light veils, until one is able to enter the divine guest house which is the “source of greatness.”
Hence, in this intimate devotion (munajat) there is a request to God, the Exalted, for vision and brightness of the heart so one may tear the veils of light and reach the source of greatness:
“Until the vision of the heart tears through the veils of light, so that there is union with the source of greatness.”
However, one who has not yet torn the veils of darkness, one who directs all of his attention to the natural world and, God forbid, becomes deviated from Allah, and one who is basically unaware of the world beyond and the spiritual worlds, and has retrogressed to a state of nature, who has never decided to refine himself, to set into motion his spiritual powers, to push aside the curtains of darkness which are a cloud over his heart.
He is lodged in ‘the deepest of the depths’ [of hell] which is the ultimate veil.
“Then we render him the lowest of the low” (Q 95:5),
While the God of the worlds has created man in the most lofty state and station.
“Indeed we have created man in the best of molds” (Q 95:4).
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