This sacred name refers to God. It embodies all adjectives of perfection. He is the Possessor and Instructor of all creation.
Allah is His name, No real existence does exist without His existence. Everybody’s existence stems from His existence.
Allah is His greatest name among His Names, when a genuine servant of God utters this word, he should get involved wholeheartedly, seeing nothing except for Him and paying no attention to anything but Him, relying on nobody except Him, and fearing nobody except Him.
A true servant of God should deny his own existence in front of His existence and should avoid pretending that he himself exists or that he is rich and powerful or else he would not be considered as a “servant” of God; rather he would turn out to be an aggressor and a tyrant.
If you carefully consider the characteristics of the Great Prophet(s.a.w), you will observe that during his sixty years of life he never noticed himself in front of Allah and repeatedly said: the most sincere and elegant poem written by Lubaid, the poet, was the following: ألا كُلُّ شِيْءٍ ما خَلا اللهَ باطِلٌ. “Be aware! Everything except for God is non-existence.”
source : The Book: Diar Aashiqan by prof, Hussain Ansarian