Lubb (essence) is the greatest mountain and the most secure maqām (spiritual station). Lubb is like the quṭb (spiritual pole); it does not move from its place and does not shift. Moderation in religion is with it. All lights, in a ḥāl (spiritual state) that surrounds it, turn towards it. These lights are only completed and manifest their strength through the ṣalāḥ (soundness) and stability of the lubb. These lights are only stabilized by the steadfastness of the lubb and exist only through its existence. This lubb is the source of the light of tawḥīd (the oneness of God) and tafrīd (affirmation of God's uniqueness). The servant's realization of the ḥaqīqa (inner reality) of tajrīd (divestment) and the illumination of tamjīd (glorification of Allah) are made firm and valid through it. This lubb is a light that draws near, a sown crop, and an intellect that reflects its particularity. It is not like the compounded particularities placed within the nafs (the lower self). It is a light laid down like the hardest of bodies.
This lubb, which is intellect, is sown in the field of tawḥīd. Its soil is irrigated with the water of grace from the sea of tamjīd, and it is the light of tafrīd. It is so irrigated that its veins are filled with the lights of yaqīn (certainty). Allah the Exalted has undertaken its cultivation and has done so directly, without intermediary, by His power, and has planted it in the garden of riḍā (contentment with God's decree). Then, so that the animal soul (nafs) does not approach these seas with its shahwa (carnal desire) and ignorance, or so that any worm (microbe) from the traits of the nafs such as arrogance, foolishness, or calamity—like the wild beasts of the desert of misguidance—does not come near, He has protected it with strong fortresses, and has made it firm in pre-eternity, post-eternity, and primordiality. (Bayān, 70)
Lubb is only attained by the people of iman (faith) who turn towards obedience to the Master (Allah), and who have turned away from the nafs and the dunya (the world). Allah has clothed these people of iman in the garment of taqwā (God-consciousness), protected them from various tribulations, named them "those possessed of lubb" (ulu'l-albāb, people of intellect), addressed them with His speech, reproached them with various admonitions, and praised them in many places in His kitāb (Book). As Allah the Exalted says: "So fear Allah, O you of understanding" (al-Māʾida 5:100). (Bayān, 72)
Lubb is intellect. However, there is a difference between them like the difference between the light of the sun and the light of a lamp, though both are light. This is certain. For you will not find two people whose intellectual power and light are equal. The intellect in one is distinguished by an unseen and unmanifest surplus that is not present in the other. What do you say about the one whom Allah has singled out with maʿrifa (gnosis, experiential knowledge of God), honored with the gifts of His generosity, and caused to flow from the seas of His goodness that He has not given to others? (Bayān, 73)
Kishr (outer shell) is every kind of knowledge that protects the gaze of the realized from being corrupted by what is manifested to it.
Lubb is knowledge protected from hearts attached to the material world. (Iṣṭilāḥ, 539)
Kishr, just as the sharia (the sacred law) protects the tariqa (a Sufi path/order), and the tariqa protects the ḥaqīqa, is all the outward sciences that protect the inner, essential knowledge (bāṭinī ʿilm) from corruption. Whoever does not protect his ḥāl (spiritual state) and tariqa with the sharia, his state becomes corrupt and his tariqa turns into whim, caprice, and delusion. Whoever does not reach the ḥaqīqa through the tariqa and does not protect the ḥaqīqa with the tariqa, his ḥaqīqa becomes corrupt and turns into heresy and atheism. (Kāshānī, 144; Jāmiʿ, 93)
Lubb is the intellect illuminated by the nūr al-quds (light of sanctity), purified from the shells of delusion and ḥayāl (imagination). (Kāshānī, 72; Jāmiʿ, 94)
(See also: ʿaql; qalb)