Niyabat-e ˓amma (Ar., niyabat al-˓amma) is a term most commonly used in Imami jurisprudence to refer to the "general delegation" of religious authorities and to the Imami ulema in the absence of the imam. In early Shi˓ism, there was an acceptance that the imams, when present, designated a particular individual (na˒ib) to perform particular tasks on behalf of the imam. With the imam's absence (ghayba), a notion that the scholars (and more specifically the jurists) were delegated (niyaba), as a class, to perform certain functions normally reserved for the imam developed in the juristic writings of scholars such as al-Muhaqqiq al-Hilli (d. 1277) and his influential pupil al-˓Allama al-Hilli (d. 1325). The delegation was eventually extended, through a series of reinterpretations of the imams' words, to refer to a "general delegation" of the scholarly class to take the place of the imam in those areas of the law where his presence is normally essential. The work of ˓Ali al-Karaki (d. 1533) and al-Shahid al-Thani (d. 1588) in this area represent the earliest expressions of this doctrine. These areas of law included duties such as the distribution of the religious levies, zakat and khums, the leading of Friday prayer and, eventually, the waging of the jihad. The "general delegation" theory provided the basis for the more directly political theory of wilayat al-faqih (Ar., velayat-e faqih) developed by Ayatollah Khomeini in the 1960s and 1970s.
Arjomand, Saïd Amir. The Shadow of God and the HiddenImam. Albany: State University of New York Press, 1984.
Calder, Norman. "Legitimacy and Accommodation in Safavid Iran: The Juristic Theory of Muhammad Baqir al-Sabzavari." Iran 25 (1987): 91–105.