Imam Khomeinisheds light through his famous book "an exposition on Forty Hadith" on the subject as following
So, the jihad al-nafs or the internal struggle is of great significance for all great religious thinkers, mystics, and moralists. It can be rather considered as the origin and the source of all felicities or woes, and of promotion and sublimation or debasement and degradation of self.
One should be extremely self-conscious while undertaking this jihad. Because, it is possible that, God forbid, due to the defeat of heavenly forces, the self is left vacant for the unholy occupation of the vicious and unworthy satanic legions, and hence causing an eternal loss to the human being that cannot be retrieved.
Even the intercession of an intercessor cannot save him from becoming an object of the wrath and indignation of the Most Merciful of the merciful. It is also possible that man’s intercessor may become his adversary.
It is a pity that such a thing should happen to anyone that one who pleads for him should become his opponent. God alone knows that what misfortunes, what perils and what hardships are to follow Divine wrath and antagonism of God’s friends, compared to which all the infernal fires, plagues, evils, serpents and scorpions are insignificant and mild.
God forbid, whatever sufferings of hell have been described by saints, ascetics, and mystics, compared to them all the imaginable pains and sufferings of this world are very mild, Imam further explained.
All of the torments about which we have heard, are trifle and insignificant when compared to the miseries one has to undergo in the Hereafter. Heaven and hell whose account has been given in the Book and in the traditions of prophets of God are certainly the heaven and hell of wicked actions, and are prepared for rewarding or punishing good and bad human deeds.
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