The answer to this question is found in three types of verses in the Holy Qur’an. One in which orders for prayers have been given. Second in which promise has been given for pardon to God-fearing persons. Third, in which Allah says that He will pardon those whom He wishes.
Hence in Chapter Ai-Imran verse 129, it has been clearly said: “He forgives whom He pleases” Idle, care-free and those shunning prayers have set aside completely the two kinds of verse and have taken shelter behind the third kind of verse. Momins cannot even think of such things. But if such a belief creeps into the mind of a Musalman he should at least think that if he actually prays with devotion and sincerity Allah is not so unjust that He will not fulfill His promise. But if the objector is a non-believer here are points for his consideration.
As Allah is the creator of man He is much more aware of his nature and temperament as he himself is not. He knows that there are people who offer customary prayers which are bereft of sincerity. There are many who are cheats and pray only so that they may be taken to be holymen and elevated souls so that they may take full worldly advantage and become famous. Allah will never pardon such persons though they may present their prayers as a token of love on the day of resurrection. Over and above this there is a psychological point in it. It is this that those who really pray Allah with heart and soul may not be proud of their prayers and be oblivious of the mercy of Allah in the light of these verses. If there would not have existed this verse after prayers for a long time people would have thought that they have prayed enough and now even Allah is not strong enough to throw them in hell.
Having ingrained this type of thinking, slowly and slowly they would have been bereft of the fear of Allah unknowingly and they would have lost all the spiritual beauty and bounty. My writing may not be taken for that Allah has said so just for convenience otherwise He is not powerful enough to throw his real worshippers into hell. May Allah forgive me. I have said that Allah is really competent and strong enough to pardon the sinners and throw the real believers in hell. And he has shown immense gratitude towards his obedient subjects by opening up this reality and saving them from wrong path.
In order to further illustrate the above mentioned facts I draw your attention towards two non-Muslim beliefs. Christians believe that having crucified himself, Lord Christ has paid for the atonement of Christians. Hence now any Christian may sin and sin he will not be thrown into the hell. What can be the psychological effect of such teachings? Will he play with sins and bad acts, or will he save himself? Decide yourself about it. Similarly the Hindus believe in Karma “action”, that is man will get the reward of his good deeds and punishment for his bad deeds automatically. Alllah is not competent enough to punish the good fellows and pardon the sinners. This belief also makes man oblivious of the Bounty of Allah. Such a man can never be God-fearing.
The link with Allah is maintained only till we have His fear and expectation. But the two above mentioned beliefs psychologically cut completely the link with Allah. Will you still disbelieve the quality of Islamic teaching? Pray remember that it will not be asked why you remained poor? Why did you not attain knowledge? You will be only asked that when you had accepted Islam willingly and cried hoarse in your belief for Islam why you not acted upon the injunctions of the Holy Qur’an. Why did you act upon forbidden injunctions and why did you not perform those acts which were ordained by Me?
(for detail pls read book)