Al-Khattābī said:

“The speculative theologians who pursued excessive subtleties did not stop there: they discussed the spirit, divine decree, the attribution of justice and the admission of possibility. They discussed the soul, the intellect, and the relationship between them, and matters that neither concerned them nor benefited them in any way—such as discussions of the indivisible particle, the leap, and similar matters that serve no purpose and yield no benefit. The scholars therefore warned against delving into these matters, fearing their temptations and the further paths they might open, leading a person into various objectionable things: repugnant statements and corrupt doctrines. They considered it best to confine discussion to what the religion has explained and the revealed law has established.”

I say: Al-Khattābī thus included among blameworthy theological discourse both what a person cannot grasp through reason and what offers no benefit. As for what a person cannot grasp through reason, if he speaks about it without knowledge, Allah has condemned speaking without knowledge in His Book. What offers no benefit belongs to the category of things that neither concern nor benefit a person, and to knowledge that brings no benefit. The Prophet, may Allah bless him and grant him peace, sought refuge from knowledge that brings no benefit.

Hence the saying: Knowledge is what is established by evidence, and beneficial knowledge is what the Messenger brought. These are the two categories that Abū Hāmid and others mention when describing fields outside the religious sciences. He says:

“They consist either of sound knowledge that offers no benefit—and we seek refuge in Allah from knowledge that brings no benefit—or of false conjectures that cannot be trusted; indeed, some suspicion is sinful.

“The first includes knowledge of the finer details of astronomy, the movements of celestial bodies, and other matters which, after much toil, yield nothing but wasted time and the torment of living beings.