KASB – كسب
Literal: An earning. Gaining. Acquiring; acquisition. To earn, gain, acquire.
In Fiqh: The inclination of a human being which cannot create. That is, to incline toward an action.
“Why are the shaytans created and brought into existence? Janâb-i Haqq created the shaytan and sharrs; what is the hikmah in it? Isn't the creation of sharr, sharr, and the creation of ugly, ugly?
The Answer: Hâsha!, the creation of sharr is not sharr, the kasb of sharr is sharr. Because creation and bringing into existence look to all the consequences, for kasb is a setting concerning the execution of a particular act and contiguity particularly, it looks to a particular result. For example, there are thousands of consequences for rain coming, and all of them are good. If through misuse of will, some people receive harm from the rain, they cannot say that the creation of rain is not rahmah, they cannot judge that the creation of rain is sharr. Rather, it became sharr for them due to the misuse of their will and kasb. Also, there are many benefits in the creation of fire, and all of them are khayr. But if some receive harm from fire through their misuse of the fire and their kasb, they cannot say that the creation of fire is sharr; because it was not only created to burn them. Rather, they thrust their hands into the fire which cooks his food through misuse of their will and made that servant of theirs enemy to themselves.” The Twelfth Letter-Your Second Question
“Question: The Mu'tazilite Imams consider the creation of sharr to be sharr, they do not attribute the creation of kufr and dhalâlah to Allah, as if by doing so they exonerate Allah. They go to dhalâlah through saying: "Man is the creator of his actions."…
… As is explained in the Risale on Qadar1 the creation of sharr is not sharr; rather the kasb of sharr is sharr, as the creation and bringing into existence look to the general results. Since the existence of sharr is an introduction to many results with khayr, the creation of that sharr becomes khayr and is equivalent to khayr concerning those results. For example, the fire has a hundred results with khayr, but certain people cannot say “the creation of fire is sharr”, through making the fire sharr for themselves due to misusing their will. In the same way, although the creation of shaytans has many results with hikmah like the progress of man; through being defeated to the shaytan due to man misusing his will and his mistaken kasb cannot say “the creation of shaytan is sharr”, as he did sharr to himself due to his own kasb.
Yes, since the kasb is a setting concerning the execution of a particular act and contiguity particularly, it has a particular result with sharr; that kasb of sharr becomes sharr. But since creation looks to general results, the creation of sharr is not sharr, rather, it is khayr. Because the Mu'tazilites did not understand this mystery, they said: "The creation of sharr is sharr, and the creation of ugly, is ugly." And in order to exonerate Janâb-i Haqq, they did not attribute the creation of sharr to Him; they fell into dhalâlah. They wrongly interpreted a pillar of îmân which is وَبِا لْقَدَر خَيْرِهِ وَ شَرِّهِ 2 .” The Thirteenth Flash-7th Indication