It is obligatory for the believer to gain knowledge of Allah, His attributes, and existence. There is no dispute about this among the scholars.
Surah Muhammad 47:19
Know that there is no god but Allah.
The Ash’ari theological perspective holds that Shariah or divine revelation is what makes someone legally responsible (mukallaf) to know Allah and His attributes. They contend that reason alone, without revelation, cannot determine the proper ruling of an action. As such, there is no inherent obligation to know or affirm certain truths or legal rulings through intellect alone. Consequently, even if one were to recognize the existence of a Creator purely through reason, without revelation, this would not be considered meritorious according to Ash’ari thought. All rulings and obligations are ultimately established by revelation.
The Maturidi theological perspective slightly differs in that they believe that faith in a Creator and His attributes can be known solely through the process of reasoning. They assert that while Allah ﷾ ultimately necessitates belief in Him, reason serves as the means to understand it as a pre-condition for the necessity of having belief, similar to how divine laws are communicated through the Prophet Muhammad ﷺ. For the Maturidis, reason has the capacity to know and discern certain Divine rulings. Therefore, unlike the Ash’aris, the Maturidis hold that even without messengers, reason could lead individuals to know of God’s existence by interpreting the signs of Allah ﷾ in creation.
Al-Bayadi states in Isharat al-Marām that:
By the mere presence of reason during the period of deduction, it is necessary to have knowledge of His, the Almighty’s, existence, His oneness, His omniscience, His omnipotence, His speech, His will and the contingency of the universe.
Both the Ash’aris and Maturidis agree that it is only Allah ﷾ Who decides whether something is good or bad, and that all rulings come from Allah and not from the intellect in and of itself.
In contrast, the Mutazila posit that it is exclusively through reason that one recognizes the necessity of knowing Allah. They view revelation merely as a support and validation for what the intellect discovers, holding that revelation can never contradict reason. Accordingly, it is the intellect that determines what is good and evil, making the necessity of belief incumbent upon reason rather than revelation.