"0 followers of the Book! Indeed Our apostle has come to you making clear to you muck of what you concealed of the Book and forgiving muck; indeed, there has come to you light and a clear Book from Allah. With it Allah guides him who seeks His good pleasure into the ways of peace wad brings diem out of utter darkness into light by His will wad guides them to the right path.
Holy' Qur'an (5:15-18)
Religion represents the work of deliverance, the message of salvation, and the torch of light, guidance and peace.
It is evidence of Allah's kindness, Exalted be He, and the result of His mercy to man, as He willed that man be His viceroy on earth.
Allah has bestowed on him powers and capabilities and has thus made him superior to all His creation.
So, man, indeed is in need of the message of religion, and the guidance of Allah, Who paved for mankind the path to light and peace, and prepared for him the means of living in happiness, prosperity and brotherhood.
Man, this tormented and unhappy creature, who suffers at the hands of modern forms of ignorance, injustice and oppression, and who endures the pains of hunger and of deprivation in its hell, and who wallows in the shadow of its darkness, in the filth of vice and squalor lives in doubt and in loss.
Man has descended to the pits of meanness which has deprived him of his freedom and will, taken away from him his security and dignity, and robbed him of the very means of living and the comforts of life. All this because he has revolted against Allah's will, and refused to respond to the message of Heaven. Instead he has thrown himself into the labyrinth of straying, wrong-doing and unhappiness. As a consequence of rejecting the leadership of faith, he has lost the right path and extinguished the torch of light by pursuing dark and unknown ways of life. Allah has truthfully said:
source : http://www.al-shia.org