Allah made belief to be purification for you from polytheism. He made:
Prayer - An exaltation for you from conceit.
Alms - A purification for the soul and a (cause of) growth in subsistence.
Fasting - An implantation of devotion.
Pilgrimage - A construction of religion.
Justice - A harmony of the hearts.
Obeying us (Ahlul-Bayt) Management of the nation.
Our leadership (Ahlul-Bayt). Safeguard from disunity.
Jihad (struggle) - A strengthening of Islam.
Patience - A helping course for deserving (divine) reward.
Ordering goodness (Amr Bi Maruf) Public welfare.
Kindness to the parents - A safeguard from wrath.
Maintaining close relations with one’s kin-A cause for a longer life and multiplying the number of descendants.
Retaliation (Qesas) -For sparing blood (souls).
Fulfillment of vows - subjecting oneself to mercy.
Completion of weights and measures - A cause for preventing the neglect of others’ rights.
Forbiddance of drinking wine - An exaltation from atrocity.
Avoiding slander - A veil from curse.
Abandoning theft-a reason for deserveing chastity.
Allah has also prohibited polytheism so that one can devote himself to His Lordship.
Therefore;
Fear Allah as He should be feared, and die not except in a state of Islam;
Obey Allah in that which He has commanded you to do and that which He has forbidden, for surely those truly fear among His servants, who have knowledge.
source : http://www.yafatima.org/