Sufism is the attempt of the individual mystic to achieve union with the divine Beloved, the Absolute from which human beings are separated by their base selves.
It typically involves a regimen of at least moderate self-denial, regular prayers, supplications, and the recitation of spiritual formulas and the divine names, and group chanting and textual study.
Among the greatest of Sufis were Rabi`a of Baghdad, Junayd, al-Hallaj, Bayazid Bistami, al-Ghazali, Ibn al-`Arabi and Jalalu’d-Din Rumi.
`Irfan is a later, especially Iranian and Shi`ite tradition of mysticism that is more individualist and more metaphysically oriented than many of the formal Sufi orders in Sunnism. Great figures here include Mir Damad, Mulla Sadra, Muhsin Fayz Kashani, and Shaykh Ahmad al-Ahsa’i.