Faith is called “something that is not natural,” since it is above reason. Within reason is called “natural,” and it is imprinted within man that what he understands and feels, he can do.
Moses is called “faith above reason,” and Korah is called “reason,” as our sages said, “Korah was clever.” Hence, Korah’s sin was that he disputed Moses, and not the Creator. Korah said that Moses fabricated and did not speak from the mouth of the Creator.
This is why the sin was so grave, since his view was against the way of faith. This is why Moses asked the Creator to punish him also in a manner of above reason, to show the whole of Israel that the work, the reward, as well as the punishment are all above reason.
Concerning the reward being above reason, it is in the manner of “if you labored and found.” That is, after a person exerts himself in accepting the burden of the kingdom of heaven, he is rewarded with things he never thought he would achieve. This is why it is called “finding,” since he never thought about it. This is why it is regarded as coming to him absentmindedly, as though he found it, as our sages said (Sanhedrin 97a).