Its non-existence induces and involves one in sin. It is the medium of exhorting towards virtue and steering one away from sin. All beings fear the one who fears Allah Ta'ala . Allah Ta'ala has stated that in the servant, two fears will not combine. In the hadith it is also stated that on the Day of Qiyamat, Allah Ta'ala will proclaim to the Malaa'ikah to remove from the Fire anyone who had at any time or occasion feared Allah .
Fear is thus incumbent for every Mu'min.
There are two reasons for this need. The possibility of one committing voluntarily an act of disobedience in the future. The possibility of some act of disobedience having been voluntarily committed, but due to negligence one's attention has been diverted therefrom. Such diversion is also a voluntary act of disobedience. When fear is effaced, anarchy is the consequence in the land.