Imam Khomeini explained the matter through his famous book "the combat with the self" as following:
Should this be a cause of disagreement among you, to corrupt the society? Suppose that, like the worldly people, you had a comfortable sumptuous life, and that, God forbid, you spent your life on feasting and drinking.
After your life is over, you would see that your life had passed like a pleasant dream, but the requital and liability for it will be with you always.
What values does this fleeting and apparently sweet life have (assuming that it is very sweet) in comparison to endless chastisement? The chastisement of worldly people is sometimes endless.
The worldly people, who imagine that they have acquired the world and benefit from its advantages and boons, are remiss and mistaken.
Everyone sees the world from the window of his own environment and situation, and imagines that the world is exactly that which he has.
The physical world is broader than that which man imagines he has acquired, discovered and through which, he roams.
It has been narrated about this world with all its means and ways that: “He has never looked kindly upon it.” So, how must the other world be upon which God, the Blessed and Exalted, has looked kindly? What is the source of greatness to which man is called and what is it like? Man is too low to comprehend the source of greatness.
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