If you say that the essence itself is identical with knowing and having power, this is an obstinate denial of what is self-evident: knowledge is not identical with the one who knows, nor is power identical with the one who has power. This, too, is agreed upon by the Muʿtazilites and those who affirm the attributes.
Moreover, your statement would then really mean that the essence is distinguished in a way that necessarily entails the essence itself. Were you to say, “The essence necessitates the essence,” that would not be sound. How, then, could it be sound if its distinctness were what necessitated it? If you say that the two are not identical, this is precisely the position of those who affirm the attributes. The knowledge they affirm is what you express as “knowing,” since the particle an (“that”) followed by a verb is equivalent to a verbal noun. Thus, saying “He knows with knowledge” or “He has knowledge” is equivalent to saying, “He is characterized by knowing—He knows.” When they say, “He is knowing by virtue of knowledge, not by virtue of His essence,” most of them do not mean that knowledge necessitates an attribute other than knowledge, namely His being knowing. Rather, His knowledge itself is His being knowing. They therefore say, “He is knowing by virtue of an attribute He possesses, namely knowledge, not by virtue of an essence stripped of knowledge.” It is well known that His essence is what necessitates His being knowing. They therefore do not dispute that He is knowing by virtue of His essence, in the sense that His essence necessitates His being knowing, that He Himself has no need of anything to make Him knowing, and that nothing other than Him has made Him knowing.
As for your statement, “He has no need of an entity by virtue of which He has power, or of an entity by virtue of which He knows,” this wording is ambiguous. It could serve as an argument only against those who affirm states, who say that there is an entity—knowledge—that necessitates His being knowing. Your statement is therefore like saying, “He has no need of being knowing and powerful, and no need of knowing and having power.” Yet you concede to them that He must know and have power, and this is what they mean by knowledge and power. Thus, after this, someone’s saying, “He needs this,” or, “He does not need it,”