Imam Sajjad (a.s) was asked: “What is the best deed for God?” He answered: “After recognition of God and His Messenger (a.s), no other act is better than hating this world. There are various forms of hating this world, and there are various types of sin. The first sin committed against God was conceit which was committed by Satan when he disobeyed God when he was ordered to bow down to Adam: “He refused and was haughty. He was of those who reject Faith.” [The Holy Quran: Baqara 2:34] The next type of sin is greed which was committed by Adam and Eve (a.s). God told them:“And enjoy (its good things) as ye wish: but approach not this tree, or ye run into harm and transgression.” [The Holy Quran: Araf 7:19] But although they did not need the fruit from that tree, they ate it and this greed remained with their offspring until the Resurrection Day. That is why the people (who are all the children of Adam) collect things that they do not need. The next type of sin is jealousy which was first committed by Adam's son when he killed his brother out of jealousy. Several things are derived from jealousy: love for women; love of this world; love to be a boss; love of comfort; love to talk; love for position; and love for wealth. There are seven characteristics all together, and they all share the love for this world. That is why the Prophets and the wise men after recognizing it have all said
“The love for this world is the root of all sins. This world is of two types: the world that is a means of our delivery to the Hereafter, and the damned world.”