The one who fears to stand in front of Allah does not indulge in sin. If he slips and commits a sin, in a moment of human weakness, his fear of facing Allah will lead him to repent and pray for forgiveness. Thus he remains within the area of obedience, the central point of which is the control of one’s caprice and desires. Indulgence of desire and caprice is essentially the cause of all forms of tyranny and transgression. It is the spring of evil. Man hardly ever falls for any reason other than succumbing to caprice and desire. Ignorance is easy to cure. Desire, after ignorance has been cured, is the plague which requires a long and hard struggle to overcome.
The fear of Allah is the solid defense against the violent attacks of desire. Indeed, there is hardly any other defense which can withstand such attacks. Hence, the surah mentions the fear of Allah and the control of caprice together in one verse. This fact is here asserted by Allah, the Creator of Man and the only one Who knows the human soul, its weaknesses and their effective cure.
Allah does not ask man to suppress his desires, because He knows that it is not possible for him to do so. He simply asks man to control his desires and not to let them control him. He tells him that fear of standing before his Lord, the Almighty, should be of great help to him. He has fixed his reward for this hard struggle: Paradise as a dwelling place, for Allah knows perfectly well the hardships involved in this struggle and the high standards to which man is elevated by it.
This struggle and self control and elevation help man fulfill his humanity.