Muslims know that Allah knows all things before they come into being, through His eternal, beginningless knowledge, which is inseparable from His holy Essence. He does not derive His knowledge of them from them:
“Does He who created not know, while He is the Subtle, the All-Aware?”
This verse establishes the necessity of His knowledge of all things in several ways, encompassing the rational proofs advanced by practitioners of speculative theology, philosophers, and others who engage in reflection and reasoned inference.
First:
He is their Creator, and creation means bringing things into being according to a determined measure. This entails determining them in His knowledge [before] they come into external existence.
Second:
This necessarily entails will. Will and volition necessarily entail conceiving what is willed and being aware of it. This is the well-known line of argument used by most practitioners of speculative theology.
Third:
All things proceed from Him, and He is their sufficient cause. Knowledge of a thing’s source and cause necessarily entails knowledge of its resulting effect. His knowledge of Himself therefore necessarily entails knowledge of everything that proceeds from Him.
Fourth:
He is, in Himself, Subtle, perceiving the finest details, and All-Aware, perceiving what is hidden. This is what knowledge of things entails. The necessary consequence must exist because its sufficient cause exists. Thus, in His knowledge of things, He is self-sufficient and independent of them, just as He is self-sufficient in all His attributes.
Then, when He sees things after they come into existence, hears His servants’ speech, and so forth, He perceives only what He has brought into being and created—what depends upon Him and needs Him in every respect. In His knowledge and perception, He has absolutely no need of anything other than Himself. It is therefore impermissible to say that He derives His knowledge of things from the fixed entities themselves, supposedly independent of Him in their fixed existence.