Imâm-ı Rabbânî ‘rahmatullâhi ’alaih’ in his book Ma’ârif-i Ladunniyya, in the Twenty-sixth Ma’rifat, explains ‘Fanâ’ as follows:
Fanâ means to forget everything except Allâhu ta’âlâ. Each of the five latîfas in the ’âlam-i emr has a picture, a likeness in man. These five lâtîfas have been given the names heart, soul, sir, khafî and akhfâ.
Most of the Awliyâ, being unable to differentiate between them, called all of them “the soul.” When referred to as “the soul,” these five things are understood. [We are made of matter, and live among material beings. Beings that are made of matter consist of the seven heavens, and the Kursî, and the ’Arsh. These nine classes of beings are one within the other, like the layers of an onion. The outermost one is the ’Arsh. Each layer is very much larger than the one within it. It is like the greatness of the ocean in comparison to a drop of water. There is no matter outside the ninth layer, which is the ’Arsh.
These beings which are not material are called the ’Âlam-i emr’ (beings of command) because they were created with the single command “Be!” Classes of material beings that consist of the nine layers are called the ’Âlam-i khalq’. ‘Khalq’ means ‘dimension,’ that is, matter. The ’Âlam-i khalq was created in seven days. The building stone of the ’Âlam-i khalq is matter. The building stone of the ’Âlam-i emr is called “latîfa.” The ’Âlam-i emr is made of various latîfas. Out of these, samples of five of them were given to men. Profound Islamic savants were able to understand these latîfas and even their originals in the the ’Âlam-i emr. Today there is no such profound savant left on the earth. These five latîfas existing in men were given the names heart, sir, soul, khafî, and akhfâ.
Even such great savants as Imâm-i Ghazâlî were unable to differentiate them from one another and called all of them “the soul.” Very few savants, such as Imâm-i Rabbânî, were able to recognize them one by one.] The soul, i.e. the latîfas, used to know Allâhu ta’âlâ before it united with this body. It used to have a little inclination, knowledge, and love towards Allâhu ta’âlâ. It had been given the strength and potential to become exalted and promoted. But it could not improve before uniting with this body; to improve it had to unite with the body. For this reason, first the soul was given an affection towards this body. Thereafter, it was allowed to go towards the body. It threw itself upon the body. Being very fine and very expansive, it sank and penetrated all parts of the body. It became unrecognizable, unknown in the body.
It forgot about itself. It began to think of itself as the body. It lost itself in the body. Thus, most people consider themselves only as bodies. Being unaware of the existence of the soul, they deny it. Allâhu ta’âlâ, being very merciful, sent messages to men, i.e. to souls, through Prophets ‘’alaihimussalawâtu watteslîmât’. He invited them to Himself. He prohibited them from being dependent upon this dark body. People who were predestined to be good in eternity obey Allâhu ta’âlâ’s commandments and put an end to their dependence upon the body. They bid farewell to it and go back up to their former heights. Once the soul regains its bearings towards its origin, so will its love for its origin that it had had before uniting with this body, gradually getting strength, and its amour with the ephemeral being gradually losing its grip. When that gloomy and inglorious paramour is completely forgotten and love felt for it is thoroughly gone, physical Fanâ (Fanâ of the body) will be attained.
Thus the first one of the two basic phases in the way of ‘Tasawwuf’ will have been passed. Thereafter, if Allâhu ta’âlâ blesses (the owner of) that soul with His Favour and Kindness, the progress will continue further ahead, a phase of selfoblivion will commence. This oblivion will gradually grow, until the self is completely forgotten about. Awareness of all beings, except that of Allâhu ta’âlâ, will be completely gone. Hence the spiritual Fanâ (Fanâ of the soul). The second phase also has been passed now. The soul’s coming to this world has been intended for its attaining this second Fanâ. It could not have attained it without coming to the world. If the lâtifa of the heart, which is called Haqîqat-i Jâmîa, passes beyond these two steps together with the soul, it will attain its own Fanâ together with the soul. If the nafs accompanies the heart in – 120 – this way, it will be purified, too. That is, it will attain its own Fanâ. But, when the nafs reaches the heart’s grade, if it remains there instead of getting exalted and passing beyond these two steps, it will not attain oblivion. It will not become mutma’inna. A person who has attained the Fanâ of the soul may not attain the heart’s Fanâ.
The soul is like a father to the heart. And the nafs is like a mother to the heart. If the heart has an inclination towards the soul, who stands for its father, and turns away from the nafs, who stands for its mother, and if this inclination increases and draws the heart towards its father, it will reach its grade. That is, it will pass beyond these two steps. When the heart and the soul attain Fanâ, the nafs does not necessarily attain Fanâ.
If the nafs has an affection, an inclination towards her son, and if this inclination increases and makes her reach near her son, who has reached his father’s grade, she will be like them. Attainment of Fanâ on the part of each of the other three latîfas, ‘sir’, ‘khafî’, and ‘akhfâ’, takes place through the same procedure. The memories’ and thoughts’ being rubbed out and removed from the heart signifies the fact that it has forgotten the things other than Allâhu ta’âlâ. Not to be able to remember anything means that knowledge of everything else is gone. In Fanâ, knowledge has to be wiped out. Why don’t you perform the ‘fard’ and the ‘sunnat’? To Hadrat Muhammad aren’t you an Ummat? Don’t ‘Hell’ and ‘Paradise’ ever occur to you? Is that what ‘a slave with belief’ mean to you?
 Religious knowledge that cannot be comprehended through the five senses or through the intellect can be learned from the Prophet’s words. Within religious information there is such knowledge which cannot be recorded in books or which cannot be explained through words. No words can be found to explain pieces of that knowledge. They are called ma’rifats. A ‘murshid’ is a great Islamic scholar and a blessed Walî who possesses such ma’rifats. They can be obtained only as a result of flowing from the murshid’s heart or from the dead ones’ souls into the hearts of those who desire them. There are conditions to be fulfilled for attaining this.
 Please see the twentieth, the twenty-first, the twenty-second, and the twenty-third chappers of the sixth fascicle of Endless Bliss.