Fear is an uneasy expectation that something unpleasant might happen. For example, one may be afraid of boarding a ship or sleeping all alone in a house. It is clear that there is a difference between cowardice and fear.

Fear is of two kinds. Firstly, there is the fear of Allah and fear of sins and Divine punishment. Secondly, there is the fear of things other than Allah. The first kind of fear is praiseworthy, and leads man to perfection; whereas the second kind of fear is an undesirable vice brought about by the disease of cowardice.

Inappropriate fear is caused by the possibility that something unpleasant might happen either to oneself or something or someone dear to one. For example, one may be afraid of death, fatal danger, dead bodies, demons, etc. The root cause of these fears is spiritual weakness, which can be removed by self-examination. For example, if one realizes that he can do nothing to avert certain or probable danger of death and that fear is of no use .in averting it, he will gradually lose his fear. If his fear of death is caused by an inordinate love of the world and material things, he must reduce this attachment.

Some fears have imaginary causes, such as the fear of darkness and dead bodies. In such cases, one should put aside one's fancies and strengthen one's soul.

The appropriate and praiseworthy kind of fear is that of the majesty and greatness of Allah. This fear is also called khashyah or rahbah. It is also the fear of sins one has committed and their punishment. The greater such fear is, the greater the contribution it can make towards one's spiritual development and perfection. Moreover, the greater and the deeper one's understanding and knowledge of Allah is, the greater his fear of His power shall be. The Holy Quran says:

... Even so only those of His servants fear Allah who have knowledge ... (35:28)

Thus in accounts of the lives of saints, we find that occasionally they would faint because of the intensity of their fear of Allah.

Intense fear of Allah is the best controlling force over human spirit; because it weakens lustful and selfish desires, keeps the self from rebellion and sin, and tames the human heart into submission to Divine commands. Furthermore, fear of Allah annihilates all other fears, making one strong in confronting injustice, tyranny, and oppression. Speaking of such people, the Holy Quran says:

... theirs is safety; and they are rightly guided. (6:82)

And

... So fear not mankind, but fear Me ... (5:44)

And

... Allah is well pleased with them, and they are well pleased with Him; that is for him who fears his Lord. (98:8)

And

But as for him who feared the Station of his Lord and forbade his soul from lust, surely Paradise shall be the refuge. (79:40-41)

And the Prophet (S) is reported to have said:

Whoever fears Allah, He will make all things fear him; whoever is not afraid of Allah, He will cause him to be afraid of everything.

There are many Quranic verses as well as traditions about the merits of being in fear of Allah; however, for the sake of brevity, we abstain from mentioning all of them here.

It must be kept in mind that even in fearing Allah one must be careful to stay within the bonds of moderation, so that it should not make one lose all hope in the mercy of Allah; since losing one's hope in the mercy and compassion of Allah is itself a great sin. The Quran says:

... And who despairs of the mercy of his Lord save those who are astray? (15:56)

If the fear of Allah has been taken to such an extreme, then it must be counterbalanced with raja' or hope in the mercy of Allah; for, with the aid of the two wings of hope and fear an individual can ascend to the highest levels of human perfection. The Quran refers to this point in these words:

Tell My servants I am the All-Forgiving, the All-Compassionate, and that My chastisement is the painful chastisement. (15:49-50)