Intellect is the tongue of the spirit (rūḥ) and the interpreter of basīra (spiritual insight). Basīra is to the spirit what the heart (qalb) is, and intellect is like its tongue.
Basīra is a faculty belonging to the heart (qalb), illuminated by the light of the Holy (Kuds). Through it, the heart perceives the inner reality (ḥaqīqa) and the true nature of things. The perception of the forms and appearances of things is like the eye of the nafs (the lower self). The sages have called this the faculty of rational contemplation (ʿaqlī-naẓarī quwwa). However, when it is illuminated by the lights of the Holy (Kuds) and the veils are lifted through the hudā (guidance) of the Real (God), the sages then call it the sacred faculty (quwwa qudsiyya). (Kāshānī, 37; Jāmiʿ, 78)
Basīra is the gaze of a person possessing ikhlas (sincerity). Its first subtlety is to support the report that is established by the sharia (the sacred law), knowing that it has proceeded from an Entity who does not fear the consequences. Its second subtlety is to witness the justice in drawing towards hudā (guidance) and not casting into dalāla (misguidance). Its third subtlety is that basīra is able to perceive the gushing forth of the fountain of maʿrifa (gnosis), the firmness of the ishāra (spiritual indication), and the fruition of spiritual discernment (firāsa). (Rawḍa, 488)