Hayāl is, in its essence, the reality (dhāt) in which the manifestation (ẓuhūr) of the Perfection (kamāl) of the Worshipped One (Maʿbūd) occurs at its highest degree. Do you not see your belief (ʿitiqād) in Him? In what locus and in what manner are the beliefs regarding the exclusive Names and Attributes of the Real (al-Ḥaqq) established? The locus of this belief is nowhere other than in hayāl (imagination). Thus, as required by the meaning explained, we have said that it is the reality in which the manifestation of the Perfection of the Worshipped One occurs at its highest degree.
If you understand what has been said above, the following meaning will become clear to you: hayāl is the origin of the entire cosmos. For Allah is the origin of all things (ashyāʾ). In this sense, His most perfect manifestation can only occur in the locus of that origin which has been described. And this locus is hayāl.
hayāl-i muttaṣil – hayāl-i muqayyad (continuous imagination – delimited imagination). Then the following emerges: hayāl is, from beginning to end, the origin of all worlds. Do you not see that the Messenger of God (peace be upon him) considered this world of sense perception to be like sleep? And sleep is considered to be hayāl. The Messenger of God said: "People are asleep; when they die, they awaken." This means: in this world (dunyā), while they are in their present state, realities (ḥaqāʾiq) become manifest to them. Then they realize that they were asleep. The meaning of this is not that with death a complete wakefulness is attained. For Allah has drawn a veil of heedlessness (ghafla) over the people of the isthmus (barzakh), the Resurrection, Hell, and Paradise.
Until the Real (al-Ḥaqq) manifests Himself in the proximity from which the people of Paradise will behold Allah, this veil of heedlessness will not be lifted. This heedlessness is itself a kind of sleep. In that state (ḥāl), the origin of all worlds is also hayāl. (Insān, II, 25)