A Mu'min is recognized by two essential traits-he has fear of Allah and hopes for His rewards in moderation. The Mu'min neither spends all his life in acute fear of Allah's retribution, nor has he excessive hopes of rewards! One has to bear in mind that both these excesses are sins!
Ruja means carrying hope of Allah's Mercy. A person who expects ruja but continues with his sinful acts will be a hypocrite of the highest order. This will be tantamount to not planting the saplings in the soil and expecting to reap the fruits.
Imam Zain-ul-'Abidin (A.S) says, "O my Lord! When my attention goes to my sins, I become fearful of retribution, but I am also hopeful of Your Mercy and Forbearance!"
Luqman advised his son, "O my son! Even if your good deeds are more than those of all men and jinn put together, you must fear Allah that you might attract His retribution. Even if your sins are more than all the sins of men and jinn, you must hope that Allah will have mercy on you! But hoping for rewards, one must strive to earn them! The faith of a Mu'min is not complete unless he develops the twin traits of khauf and ruja in himself!"
Allah is just and He cannot do injustice to His creatures. The rewards therefore will be commensurate with the good deeds of the individual. It is believed that Allah will reward a person ten times more than his good deeds. Allah will punish a person who is proud of his piety and reward a pious person who is humble in his piety!
Imam Jafar Sadiq (A.S) said, "O Ishaq! You must have fear of Allah as if you are in His presence! If you are not seeing Him, certainly He is seeing you! If you have a doubt that Allah is not seeing you, you are an infidel! When you have the conviction that Allah sees you all the time and even then continue with your sinful acts, then it will be tantamount to feeling that He is the weakest in whose presence you can commit sins with impunity!"
Another tradition says that people fear him who fears Allah. He who has no fear of Allah, is afraid of everything else around him! The conscience of one who has fear of Allah will not be attracted towards the wordly things.
source : tebyan
