Marja'

In Shia Islam, marjaʿ (Arabic: مرجع‎‎) (Plural: marājiʿ), also known as a marjaʿ taqlīd or marjaʿ dīnī (Arabic: مرجع تقليد / مرجع ديني‎‎), literally means "source to imitate/follow" or "religious reference", is a label provided to the highest level Shia authority, a Grand Ayatollah with the authority to make legal decisions within the confines of Islamic law for followers and less-credentialed clerics. After the Qur'an and the prophets and imams, marājiʿ are the highest authority on religious laws in Usuli Shia Islam.

Currently, marājiʿ are accorded the title Grand Ayatollah (Arabic: آية ‌الله العظمی / Āyatullāh al-Uẓmà; Persian: آیت الله عظما / Ayatollah Ozma), however when referring to one, the use of Ayatollah is not acceptable. Previously, the titles of Allamah (such as Allameh Tabatabaei, Allameh Majlesi, Allameh Hilli) and Imam (such as Imam Khomeini, Imam Rohani,Imam Shirazi and Imam Sadr) have also been used.

From the perspective of jurisprudence, during the occultation of Muhammad al-Mahdi, Shiite clerics are his representatives, with responsibility for understanding and explaining Islamic religious jurisprudence.

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