Foreword

Religious scholars have related that Allah has three thousand Names. One thousand are only known by angels, 1000 known only by prophets, 300 are in TORAH (Old testament), 300 are in Zabur (Psalms of David), 300 are in the NEw Testament, and 99 are in the Quran. This makes 2,999 Names, One Name which has been hidden by Allah is called Is-mul-laa-hil-a'zam: The greates Name of Allah.

All of Allah's Names are great, but since He has hidden this particular Name it is referred to as the Greates Name. The name is mentioned in the Quran as this Hadis status:

Asma, radiyallahu anha, reports that Prophet Muhammad, peace and blessings of Allah be upon him, said : "The Greatest Name of Allah" is in these two verses of the Quran, He who is worshipped by you is One Allah, there is no Allah but HIM, the compassionate and the Beneficent (sura ii,163); also is in the first part of sura Aa-li Imran, Alif Lam Mim - Allah, there is no God but Him, the Alive, the self subsisting."

Aisha, radiyallahu anha, mentioned that YA RAB (Oh Lord) is the Greatest Name.

Whoever reads the Quran must have read the Greatest name of Allah, pobably without knowing it. Some of the companions of the Prophet, may the peace and blessings of Allah be upon him, knew the Name. Ali Karramallahu wajhahu (the fourth caliph(, may Allah exalt him, was one who knew the Greatest name.