How did Imam advise believers about getting rid themselves from veils of darkness?

According to Imam Khomeini, 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.