(see vesm and resm)
resūl/rusul (see walī-nabī-resūl)
retk (see fatk-retk)
reyn/rān (Qur'an 83:14) Reyn is the rust upon the qalb (the heart). (al-Lumaʿ, 450)
Junayd said: Reyn is from among the waṭanāt (habituated inclinations); while ghayn is from among the khaṭarāt (passing thoughts). Waṭan (the habitual) is enduring, whereas khaṭir (the passing) is transient. Its example is as follows: No matter how many master polishers gather, it is not possible for them to make a mirror from a stone. But when a mirror becomes rusty, it can be cleaned only with a polishing tool. For rust and blackness are essential elements in the stone, while light is an essential element in the mirror. The essence is enduring; these transient qualities are not lasting. (Hujwīrī, 8)
Reyn is the veil over the qalb (the heart). This veil can only be lifted by iman (faith). This is kufr (disbelief).