The GREATEST NAME is the Name which contains the meanings of entire of the Most Beautiful Names of Allah. The supreme Name is the GREATEST which mean the supreme, the highest, and the most exalted. According to that, the Greatest Name means the most comprehensive Name among the Divine Names which comprises entire of the Names. It is not known which Name is the Greatest Name definitely. The wisdom in keeping this Name secret is to encourage the remembrance of all Names with the probability that they might be the Greatest Name.

While that wisdom is mentioned in the Risale-i Nur, the attention is attracted to the point that the night of Al-Qadr in Ramadan, the acceptance hour of prayers in the day of Friday are kept secret for that wisdom. Besides this, in the Nur Collection, it is stated that every Name has a maximum degree and the saints considering the Greatest Name to be apart from each other is explained by stating that the Names they manifest are different. The real Greatest Name is concealed; the upper class is informed of it. However, every Name has a maximum degree and that degree is considered as the Greatest Name. It is because of that secret why saints find out the Greatest Name as different Names. (Barla Lahikasi)

The following explanation is made in the Thirtieth Flash from the Risale-i Nur Collection: The Greatest Name is not the same for everyone; it differs. For example, for Imam Ali (May God be pleased with him) it was the six Names. These are Al- Ferd (Single), Al- Hayy (Ever-Living), Al-Qayyoom (Self-Subsistent), Al-Hakeem (Sapient), Al-Adl (All-Just), and Al-Kuddus (Most Holy). For Imam al-Azam, it was two Names; Al- Hakeem and Al-Adl. While for Ghawth al-Azam it was Al- Hayy. For Imam-i Rabbani, the Greatest Name was Al-Qayyoom, and so on; many other people considered the Greatest Name to be different Names. Badiuzzaman, the author of the Risale-i Nur, reminds that just as the conceal of the night of Qadr in Ramadan and the conceal of time of death in life time, the Greatest Name is concealed among the Divine Names; besides this he indicates that every Name has a maximum degree in means of manifestation. (The difference between the manifestation of the Name of Creator in the creation of a minute particle and the manifestation of the Name of Creator in the creation of the entire universe is that degree difference and the second of them expresses a manifestation at the maximum degree.)

The Greatest Name is concealed. As conceal of time of death in lifetime, the night of Qadr in Ramadan, conceal of the Greatest Name in Names have a significant wisdom. In our opinion, the real Greatest Name is concealed; the upper class (the elite persons who have a high degree in knowledge) is informed of it. However, every Name has a maximum degree and that degree is considered as the Greatest Name. It is because of that secret why saints find out the Greatest Name as different Names. A eulogy of Imam Ali (May God be pleased with him) called Ercza takes place in the Mecmuat'l-Ahzab. He mentions the greatest Name in six Names. Imam Gazali explained those six Names that were mentioned by Hadhrat Ali and that encompassed the Greatest Name and he also declared their special qualities in his treatise called Cunnetul- Esma. Those six Names are Al-Ferd, Al-Hayy, Al-Qayyoom, Al-Hakeem, Al-Adl, Al-Kuddus.

Religious scholars have related that Allah has three thousand names. One thousand are only known by angels, 1,000 known only by prophets, 300 are in the Torah (Old Testament), 300 are in Zabur (Psalms of David), 300 are in the New Testament, and 99 are in the Qur'an. This makes 2,999 Names. One Name which has been hidden by Allah is called Ism Allah Al-Azam: The Greatest Name of Allah.

Dr Sharib says :

Allah is the name of the Essence and the 99 most beautiful names are the
attributes or the qualities of Allah....According to some scholars Allah is the
al-ism al-azam, the greatest name.

As regarding the effect of the names Shah Wali Ullah of Delhi says this:

The divine names.... assume the form of luminous bodies in the Similitudinary
World, and there the angels obey them. When the Changer (God) turns them by
some kind of personal intention towards itself and pulls them to the desired object,
they incline towards it and the angels who are the servants of the divine names
yield to them.

Lamha 27. Sufism and the Islamic Tradition Trans: Jalbani. Octagon Press. 1980

Dr Sharib says:

According to the Sufis, one name of Allah manifests, dominates and exercises
sovereign control at (all) times. The name of Allah rules and governs the universe.
The name manifests His kingdom. When the period of the rule and manifestation
of one name comes to an end, then the turn comes for the rule and manifestation
of another name. The Qur'an says:
Everyday He is upon some task. (Qur'an 5:29.)

To the Sufis this refers to the manifestation of one name.

8.5 The Culture of the Sufis by Dr Zahurul Hassan Sharib Sharib Press. 1999.

IZME AZAM (Unpoken name of Allah/God)
Ism-e-Azam are the great names of Allah, when recited invokes the mercy of Allah.

Laa ilaaha illaa anta, subhaanaka inniy kuntu minaz-dhaalimeen.

Hakim narrates in his Kitaab (pg.506) of the Hadith narrated by Saad ibn Abi-Waqqas (Radhiallaahu Anhu) that Nabi (Sallallaahu Alayhi Wasallam) said, Yunus (Alayhis salaam) made this Duaa at the time he was in the whale's stomach. A Muslim who makes Duaa with this, Allah will answer such a Duaa.

There are many views regarding Ism-e-Azam. This is just one of them, but the most preferred saying is, O Allah, verily I am asking you, verily I witness that you are definitely Allah, no God besides you are Ahadus-Samad, the One Who is Independent, The One Who does not give birth nor was he given birth to and there is none equal to Him. (Tirmidhi)

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai

The Greatest of name Allah
Bismillahir Rahmanir Rahim
It stated that Allah has 3,000 names: 1,000 are known only by angels, and 1,000 only by the prophets of Allah, who include Abraham, Moses and Jesus. The hadith goes on to say that 300 names for Allah are found in the Torah, 300 in the Zabur (Arabic for Psalms of David), 300 more in the New Testament, and 99 in the Koran. This makes 2,999 names. One last name -- hidden by Allah, according to some interpretations -- is called Ism Allah Al-Azam: The Greatest Name of Allah.
So what is the Ism Allah Al-Azam or Ismul Azam (the Greatest name of Allah)?
In a hadith the Messenger of Allah has stated ''To Allah belongs a Grand Name, that, if you make a du'a with it, it will be responded to. And if you plead or request with it, it shall be answered.'' So it other words whatever is asked by this 'Great Name' Allah will for sure fullfill it Insha Allah.

It was narrated from Abdullah bin Buraidah that his father said the Messenger of Allah heard a man say;

''Allahumma! Inni asaluka bi-annaka Antallahul-Ahadus- Samad, alladhi lam yalid wa lam yuwlad, wa lam yakun lahu kufuwan ahad.'' (O Allah! I ask You by virtue of Your being Allah, the One, the Self-Sufficient Master, Who begets not nor was begotten, and there is none co-equal or comparable to Him).''

The Messenger of Allah said:''He has asked Allah by His Greatest Name, which if He is
asked thereby He gives, and if He is called upon thereby He answers.'' (Sahih, Tirmidhi, 3857)

Another tradition:
It was narrated that Anas bin Malik said: ''The Prophet (SAAW) heard a man say:
'Allahumma! Inni asaluka bi-anna lakal-hamd. La illlaha illa Anta, wahdaka la sharika laka. Al-Mannan. Badi ussamawati wal-ard. Dhul-jalali wal-ikram (O Allah! I ask You by virtue of the fact that all praise is due to You; none has the right to be worshiped but You alone, and You have no partner or associate, the Bestower, the Originator of the heavens and the earth, the Possessor of majesty and honor.)''

He salallahu alayhi wasalam said: ''He has asked Allah by His Greatest Name which, if He is asked thereby He gives and if He is called upon thereby He answers.''
(Tirmidhi)

Another tradition:
It was narrated that Anas bin Malik said: ''The Prophet (SAAW) heard a man say:
'Allahumma! Inni asaluka bi-anna lakal-hamd. La illlaha illa Anta, wahdaka la sharika laka. Al-Mannan. Badi ussamawati wal-ard. Dhul-jalali wal-ikram (O Allah! I ask You by virtue of the fact that all praise is due to You; none has the right to be worshiped but You alone, and You have no partner or associate, the Bestower, the Originator of the heavens and the earth, the Possessor of majesty and honor.)''

He salallahu alayhi wasalam said: ''He has asked Allah by His Greatest Name which, if He is asked thereby He gives and if He is called upon thereby He answers.''
(Tirmidhi)