Imam explains the matter as following:
In as much as the love of this world causes total attachment to it and makes one forget his or her objective; it gradually immerses the person in various sins and offences.
According to Imam, the first sin and offence arising from the love of the world is that man thinks of this ephemeral and temporal world as everlasting, but whenever the veil of his notion is torn, one becomes fearful and dreadful of death. As a result, it would even make him furious of God.
The other sin that spawns from love of this world is the weakening of man’s will. What makes man a man is his willpower and if, due to love of the world, this will is to weaken, then nothing would be left of his humanity.
The third sin issuing from love of this world is that man is never satiated by it and in order to get more enjoyment from it he is prone to defile himself with any sort of sin and gradually drowns in all these sins.
Imam Khomeinī describes some of the evils of loving this world in this manner:
Among the evil effects of the love of the world and attachment to it is that it makes man afraid of death… Another great evil caused by the love of the world is that… it weakens his power of resolution and debilitates the will… Since he mistakenly believes the world and worldly fascinations to be the desired ultimate goal his greed grows day by day and his desire for them multiplies. His need for the world increases and poverty and deprivation becomes his fate.
Consequently, he is like a thirsty person who drinks water from the sea and becomes thirstier.