Imam Muḥammad b. Yūsuf as-Sanūsī [rah] :Allah

One of the most celebrated later Ash'arite Imams, Imam Abū-`Abdallāh Muḥammad b. Yūsuf b. `Umar b. Shu`ayb as-Sanūsī l-Ḥasanī (died at the hour al-`aṣr on Sunday, 18 Jum. II 895/ 10 May 1490 in the city of Tilimsān in Algeria) al Maliki(Rah)  in his 'Aqidatul Kubra":

inquires about the most particular characteristic (akhaṣṣ waṣf) of Allah's Essence(Dhat) and gives the answer:

The best opinion is that of Qadi AbuBakr al-Bāqillānī, Imām-al-Ḥaramayn, Hujjathul Islam Imam Abu Hamid al-Ghazālī, and Imam Fakhr ad-Din  ar-Rāzī (Rahmatullahi Alaihim) in most of his writings-but not in his Kitāb al-ishārāt, one of his earliest writings-that the most particular characteristic of Allah's essence is unknown.

As for whether it is unknown absolutely or only in the present life, it is admissible for us to know it later. Imam Saifudin al-Amidī attributes to Imam al-Ghazālī the opinion that it is absolutely unknowable, and to al-Bāqillānī and Ḍirār b. `Amr an abstaining from judging.

Imam ar-Rāzī's argument from intelligibility that the most particular characteristic of Allah's Essence is unknwon , is that we know only four things about ALLAH:

         # Existence (WUJUD)

         #  Ways of existence (kayfiyyāt al-wujūd), which are:

                        Being from the eternal past (azaliyya)

                        Being forever (abadiyya)

                        Necessity (wujūb)

         #  Negations (sulūb), that is, he is not a body or a substance (jawhar) nor an   

accidental (`araḍ;) 

       #   Attributions (iḍāfāt), such as knowingness (`ālimiyya).

But none of these things are God's essence. Therefore it is unknown                         

                

An argument to the contrary of is the experience of the ṣūfīs.

                                

The ṣūfīs claim that their exercises (riyāḍa)  are an activating-link for Allah's willing (for them) an increase in understanding, as two Qur'ān verses show: "Those who struggle for us we guide on our paths" [29:69] and

"He wrote faith in their hearts and confirmed them with a spirit from himself" [58:22].

These refer to Allah's creating in them knowledge which is not demonstrable or expressable, but is given by way of pure and extraordinary favor (in`ām) and inspiration (ilhām) which is known only by those who possess it, not by anyone else, just as someone born blind (akmah) cannot see colors. It cannot be communicated to others by speech (qawl), but only by the beckoning (ishāra) of one who is aware (`ārif) to another who is aware. This knowledge is not an indwelling (ḥulūl), nor an anticipated vision of Allah (ru'ya `ājila), nor as great as prophecy, nor is it a comprehensive knowledge (`ilm iḥāṭa) of Allah. But as Allah creates in his servants a visual perception (idrāk) of himself in the next life, so he creates now in their hearts a perception of himself, related to the essence of  Allah in one way or another (bi-wajhin) or to a superior kind of knowledge (taraqq fī l-`ilm) of his attributes and names. "