As is mentioned in the Third Indication in the Tenth Word, the unbeliever only committed only one sin in his short life, but the sin comprised infinite wrongdoing. For unbelief is an insult to the whole universe; it negates the value of all beings, it denies  the testimony  to divine unity of all creatures,  and is contempt  towards the divine names, the manifestations of which are to be seen in the mirrors of beings. Therefore, in order to avenge the rights of beings on the unbeliever, their monarch, the All-Compelling  One of Glory, casts the unbelievers  into Hell, and this is pure right and justice. For an infinite crime demands infinite punishment.

SECOND QUESTION

Why  are  devils  created?  Almighty  God  created  Satan  and  evil;  what  is  the wisdom in it? Isn’t the creation of evil, evil, and the creation of bad, bad?

T h e  A n s w e r :  God forbid, the creation of evil is not evil, the acquisition of (kesb) or desire for evil, is evil. For creation and bringing into existence look to all the consequences, whereas such a desire looks to a particular result, since it is a particular relation. For example, there are thousands of consequences of rain falling, and all of them are good. If due to misuse of their wills some people receive harm from the rain, they cannot say that the creation of rain is not mercy or that it is evil. For it is evil for them due to their mischoice and inclinations. Also, there are numerous benefits in the creation of fire and all of them are good. But if some people are harmed by fire due to their misuse of it and their wills, they cannot say that the creation of fire is evil; because it was not only created to burn them. Rather, they made a wrong choice and thrust their hands into the fire while cooking the food, and made that servant inimical to themselves.

In Short: A lesser evil is acceptable for a greater good. If an evil which will lead to a greater good is abandoned so that a lesser evil should not occur, a greater evil will have  been perpetrated.  For example,  there  are  certainly  some  minor  material  and physical harms and evils in sending soldiers to fight a jihad, but the jihad leads to a greater good whereby Islam is saved from being conquered by infidels. If the jihad is abandoned due to those lesser evils, the greater evil will come after the greater good has gone, and that is absolute wrong. Another example: to amputate a finger which is infected with gangrene and has to be amputated is good and right, although it is apparently an evil. For if it is not amputated, the hand will be amputated and that would be a greater evil.