As for his denial of Allah’s power:

He portrays the Lord as capable only of manifesting Himself in those entities that are fixed in nonexistence and independent of Him. His power is thus bounded by them and confined to them, even though they are independent of Him and their realities are fixed without Him. This, in his view, is the secret that has rendered Allah powerless to create anything other than what He has created. According to him, Allah cannot add a single particle to the world or remove one from it, add a drop to the rain or remove one from it, increase or decrease a person’s height, or change any of his attributes, movements, or states of rest. Nor can He move a stone from its place, divert water from its course, guide someone who is astray, lead someone who is guided astray, set something motionless in motion, or bring something moving to rest. In short, He can bring about only what has actually come into existence, because the entity of whatever has come into existence is fixed in nonexistence, and He can do no more than manifest Himself in those entities.

This attribution of ignorance and incapacity, which he has set out and claimed to be the secret of divine decree—even though it incorporates some of what other misguided people have said—contains such disbelief as even other misguided people would not accept.

For those who hold that the nonexistent is a thing say this of every possible thing, whether it exists or not. They do not regard His knowledge of things as derived from those things before they come into existence, nor do they hold that His creation and power are confined to what He knows of them. For He knows kinds of possible things that He has not created; thus, the possible things encompassed by His knowledge are more extensive than what He has created. Nor do they hold that what prevents Him from creating anything other than what He has created is that the entities fixed in nonexistence admit of no existence other than this. Rather, in their view, these entities could exist with different attributes, which are likewise among the possibilities fixed in nonexistence. Their position therefore does not entail attributing either ignorance or incapacity to Him in this respect. They may, however, say: