Hadrat Imâm-i Rabbânî says in the  52nd letter of the third volume of his Maktûbât:

This letter was written for Muhammad Hâshim Keshmî ‘rahmatullâhu ta’âlâ ’alaih’, (d. 1054 [1645 A.D.], Burhânpur,) compiler of the third volume of Maktûbât. It explains the Fanâ of the heart and of the nafs and the ’ilm-i-husûlî’s and the ’ilm-i-hudhûrî’s ceasing to exist:

Fanâ means to forget about the mâ-siwâ. And mâ-siwâ, in its turn, includes all beings other than Allâhu ta’âlâ. There are two groups of mâ-siwâ: Âfâq means creatures outside of man. Enfus (or anfus) means things that are within man. To forget about the âfâq is an event that takes place when the ’ilm-i-husûlî, i.e. the knowledge pertaining to the âfâq, ceases to exist. To forget about the enfus means for the ’ilm-i-hudhûrî, whereby the enfus is known, to cease to exist. For, the âfâq is known through the ’ilmi- husûlî, and the enfus is known through the ’ilm-i-hudhûrî. It is difficult for the ’ilm-i-husûlî to cease to exist, and it is attained by the Awliyâ ‘qaddas-Allâhu ta’âlâ asrârahum-ul’azîz’. It is much more difficult for the ’ilm-i-hudhûrî to cease to exist, and it falls only to the lot of the very high ones of the Awliyâ. Most of the people who look on facts by using their mind only, deny these facts. In fact, they say that such things are unthinkable. They say that it is out of the question for a person with perception to forget about himself. They say, “A person has to be aware of himself. A person cannot forget about himself even momentarily, let alone perpetually.”

Do not take pride in your property!

Don’t ever say, “No one is like me!”

A disastrous wind will winnow all,

Making only a defenceless chaff of thee!