Imam Khomeini in his famous book of "the combat with the self" has undertaken very useful discussions as following:
Undertakers are not afraid of the dead, for they have certainty that the dead cannot harm one, even when he was alive and had a spirit in his body he was not harmful, so what harm can he be now as an empty frame?
However, those who are afraid of the dead are afraid because they do not have faith in this truth. They merely have knowledge. They know about God and the Day of Atonement, but they lack certainty.
The heart is unaware of that which the intellect has understood.
They know the proofs for the existence of God and the reality of the Resurrection, but these very same intellectual proofs may be veils covering the heart which do not permit the light of faith to shine in, Imam further explains.
Until God, the Exalted, frees them from the darkness and the obscurities and leads them to enter the worlds of light and radiances:
“Allah is the Guardian [wali] of those who believe; He brings them out of the darkness into the light” (Q 2:257).
He whose Guardian [wali] is God, the Blessed and Exalted, and who is taken by Him out from the darkness never commits another sin, never backbites, never slanders others, and he is never vengeful or envious of his brothers in faith. His own heart is filled with a feeling of luminosity and he no longer holds the world or what it contains in high esteem.
As Imam ‘Ali (as) said, “If all the world and what it contains were offered to me to cruelly and unjustly take the skin of a grain of barley from the mouth of an ant, I would never accept it.”
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