It is the arc descending from the element of earth among the elemental bodies down to the sphere of the moon (qamar). This is the densest among them. (Ravza, 556)
Intellect is the foundation of the human species. It conveys maʿrifa (experiential knowledge of God) and sciences to the nafs (the lower self) and ruh (the spirit). When the human nafs, by virtue of the principle of light and the body it governs, observes the body it governs, and as it increases the combinations, additions, states, and disorders, its essence will perceive in a single ḥāl (spiritual state) without making it the tenth intellect (ʿaql-i ʿāshir), and this perception will also be disordered. The perception of the celestial nafs, on the other hand, is the opposite. It is like the sun reflected in a mirror, which is then reflected in another mirror in an orderly fashion. Then, stage by stage, irregular gleams are reflected. These reflections sometimes become manifest and sometimes hidden, according to the disposition of intention in the highest assembly (malāʾ al-aʿlā). (Ravza, 557)
Intellect, in terms of the sciences being present in its essence in a summarized (ijmālī) manner, is nūn; in terms of their detailed (tafsīlī) exposition in the tablet (lawḥ), it is the pen (qalam). (Asfār, 245)
Intellect is that which protects you from harm and opens the doors of happiness for you. The doors of happiness are opened by it. This is the greatest intellect that receives secrets from Allah. If you are found with the smallest intellect, it will cast you into the seas of shahwa (carnal desire) and doubt, and entangle you in the net of difficulties. (Qawānīn, 92)
The development of the ruh (spirit) is from the nafs (lower self), ʿaql (intellect), qalb (heart), ruh (spirit), and sirr (innermost secret). In knowledge and perception, there is a limit at which every state comes to an end. The limit of the nafs in knowledge and perception is to be deceived by the outwardness of matter, to occupy itself with its outward aspect, to abandon the inner lesson, and to be heedless and preoccupied with the pleasures of matter. The limit of the intellect in knowledge and perception is to turn to its Creator by abandoning everything other than Him and to seek lights. Only in this way does the intellect become free from bonds, and its yearning for its Master intensifies. The limit of the ruh in knowledge and perception is to seek the secrets of jabarūt (the realm of divine power) and to turn towards the lights of malakūt (the spiritual realm). This journey...