Scholars have diverse opinions concerning Al-Ismul 'A'zam, the Greatest Name of Allah. Some of them argue that basically, all the Names of Allah are equal, they are the same; none is superior to another. They should not be compared. Such scholars include Abū Ja'far At-Tabarī, Abūl Hasan Al-'Ash'arī and Abū Hātim b. Hibbān. They hold the view that all the Names of Allah are great and  no other name is greater than them. 

The position of the scholars is the same as that of Junayd, Abū'l-Qāsim al-Baghdādī, a great Sūfī Shaykh (d.910 CE), who was approached by someone who sought to know the Greatest Name of Allah from him. He, in return, asked the man to show him the smallest Name of Allah (Al-Ismul Asghar). The man could not. 

Some scholars maintain that Allah has not revealed His Greatest Name to anyone; He has kept it to Himself. Al-Hāfiz Ibn Hajar in his Fathhul-Bārī, refers to some fourteen views including some ahadith and people who claimed to have known it in dream after praying to Allah for its revelation to them. According to Al-Hāfiz, some of them are not correct because they are based on Weak Ahādith found in Silsilatul Ahādith Da'īfah by Shaykh Al-'Albānī. 

Ibnul-Qayyim is of the opinion that, perhaps the closest of the sayings is that the Greatest Name is "Allah." It is a name not given to any other than the Supreme Being. The report of Ibn Amir Haj al-Hanafi is similar. He reported Muhammad Ibn Hasan saying:" I heard Abū Hanīfah say "The Greatest Name of God is "Allah". 

"Allah", no doubt, is a unique name peculiar to the Owner as no other being bears it, not even by any pre-Islamic being. No idol or god was so named by the Arabs. Allah is not a contraction of _al-ilāh_ . It is not a derived name. The _Al_ is inseparable from it. This Proper Name of the Divine Being has no equivalent in any other language. Allah is Allah. He exists necessarily by Himself to enable other beings exist. In spite of the uniqueness of His Name, Allah, some scholars including An-Nawawī claim that the Greatest Name is Al-Hayy Al-Qayyūm, Ibn 'Abbās reported Rasūlullāh, (SAAWS), saying:" The Greatest Names of Allah are in the last six verses of Sūratul Hashir" (Q59).  (Jāmi'ul Saghīr). 

The safe conclusion one may draw from all the above discussions is that there is no agreement on what the Greatest Name of Allah is; not even from the various ahādīth of the Prophet, (SAAWS) , who is known to be truthful and consistent. He does not contradict himself. This may explain why some of the ahādith have been classified as Weak. Perhaps it is better to stay with the scholars who maintain that there is no special name or names that should be regarded as the Greatest Name(s) of Allah but that all His Names are, on the basis that none of the Names is inferior to others. All of them are Great, Beautiful and Excellent. This is in conformity with Q17:110 & 7:180, which say that to Allah belong all the Beautiful Names. We are urged to supplicate Allah by the Names and not by a particular one(s) only. 

We do not need to spend our valuable time and money searching for the Greatest Name of Allah. All His Names are Great and none is Greater than others, or is the Greatest of all. No Muslim need to regard himself or be regarded as the intermediary between Allah and humankind. Everyone has been given the opportunity of speaking directly to Allah in any language that he or she can express their desires, emotions, feelings, aspirations, goals, wishes, etc, naturally and conveniently; obviously,  not in Arabic only but in other languages because He understands all of them, He is a Polyglot. 

We need to develop spiritually every day without depending on any intermediary. All it requires is sacrifice, discipline and sincere devotion to Allah only (Ikhlās). Q17: 57 has taught us not to look for any intermediary because the so called intermediary is looking for means of gaining access to Allah. He, too, is far from Him. Q5:35 should not be misconstrued. We are not asked to take anyone as our intermediary but to seek means of gaining access to Him, and that has been explained variously. The soundest of them to me is to engage in doing good deeds acceptable to Allah and shunning Harām, the Forbidden things as well as the Makrūhāt, the Reprehensible acts. We develop spiritually when we do all the obligatory acts and follow them with the Nawāfil, supererogatory ones such as observing Tahajjud, voluntary fasting, caring for our parents, our family, the vulnerable by giving them Sadaqah (Welfare Package), and of course,  showering lots of As-Salātu on Rasūlullāh, (SAAWS). 

If we are able to do all that are enumerated above, we shall have positive response from Allah to our supplications. We do not require any intermediary to present our requests before Allah just as we do not need any other Al-Ismul 'A'zam other than the Beautiful Names of Allah. Allah is very close to us, closer than our jugular vein (Q50 :16), He is always prepared to respond to our call if only we are responsive to His. Q2:186.