This letter, written to Khwaja Muhammad Abdullah 'sallamahullahi ta'ala', his murshid's son, informs that everything occurring to the mind or imagination and everything understood through kashf and shuhud are creatures and that they are called masiwa:

Hamd be to Allahu ta'ala and salam to those slaves of His chosen and loved by Him! The valuable letter sent by the light of my eye has arrived here. "As if they were toys on the way of tasawwuf, all the things amusing the travelers have disappeared with the help of Allahu ta'ala. Nothing is now continuous. Everything coming to my mind or imagination is disappearing as soon as I say the word 'la'," you say. You write many other similar things. You add that you have been struggling so that they will be annihilated and hoping that later on they will be annihilated spontaneously. My dear son! All the things coming to the mind and imagination, even those pieces of knowledge found out through kashf and shuhud, are masiwa, whether they are afaqi, outside of man, or anfusi, inside man. [In other words, they are the creatures of Allahu ta'ala.] To set the heart on them means to waste the time on trivial things such as playing and toys. It is to play with useless things. If their annihilation is managed by struggling, this work is, 'ilm-ul-yaqin. If they are annihilated by themselves, without struggling, the matter has exceeded the limits of a struggle and gone beyond the street of knowledge, and one has been honored with fana. It is easy to say but difficult to attain these. They are attained only by those people whom Allahu ta'ala has blessed with the lot. The things in the grade of haqiqat are attained later. After fana the grade of ithbat is attained. After knowledge the ayn is attained. The tariqat is of no value when compared with the haqiqat. Nafy [to dispel the thought of creatures from the heart] is of no value when compared to ithbat [to attain to the Purpose, the Real Being]. For, while doing the nafy one is busy with creatures. But when doing the ithbat there is nothing besides Allahu ta'ala. [In the alam-i mithal] nafy, when compared with ithbat, looks like a drop of water compared with an infinite sea. When the nafy and ithbat are reached one will attain to Wilayat-i khassa. After the wilayat-i khassa, one either does uruj, that is, goes up, or does nuzul, that is, goes back down. If one does uruj, one has to do nuzul again later. O our Allah! Increase the nur which Thou hast endowed upon us! Forgive us our sins! Thou canst do everything. Salam to you, to those who are on the right way and who have been following Muhammad Mustafa 'alaihissalatu wassalam'!