Kashaf-ul-Mahjub (unveiling the veiled)

Fana (Noughting) follows Baqa(enduring) which alludes to the abiding with God of the now illuminated spirit in the state of servanthood(abdiat)
that is;

being filled with the light of devine attributes, while he remains his own essential humanity

Hujwiri explains this by the example of iron in afire: when the iron becomes red hot, it assumes the attributes of fire, from wahich it is then indistinguishable, and in that state may proclaim "I am fire"

But the latent link with its essential reality of ironness is not sered, and in seperation from the fire it appears once again with its limited being.

Hujwiri sums up this exposition in his characteristic sentence, that

"the attributes of man are transformed, but not his essence".

Ofcourse, this is the necessity incomplete expression of a spiritual experience that is inexpenssible, but it has the great advantage of clarifying a doubt that has misled not only some mystics but whole communities.