What knowledge is required for a judge to achieve the rank of Ijtihad?
General Chapter
Al-Mughni
Book of Judiciary
Primary text
Ijtihad requires knowledge of six things: the Book (Quran), the Sunnah, Consensus (Ijma'), Differences of Opinion (Ikhtilaf), Analogy (Qiyas), and the Arabic Language. Regarding the Quran, knowledge of ten aspects related to rulings is needed: Specific (Khas), General ('Am), Unrestricted (Mutlaq), Restricted (Muqayyad), Clear (Muhkam), Ambiguous (Mutashabih), Summarized (Mujmal), Explained (Mufassar), Abrogating (Nasikh), and Abrogated (Mansukh), covering about 500 verses related to rulings. Regarding the Sunnah, knowledge of what pertains to rulings, including the classification of hadith (mutawatir, ahad, mursal, musnad, etc.), is required, along with knowledge of consensus, differences, Qiyas and its conditions, and the linguistic aspects necessary for derivation.
Supporting text
It is not required that the judge possess an exhaustive grasp of all these sciences, nor is he required to know all subsequent juristic rulings derived by later Mujtahidin, as these are subsequent to achieving the rank of Ijtihad. Moreover, capacity for Ijtihad is established for a specific issue if the person knows its evidence, even if he is ignorant of other matters, as demonstrated by Abu Bakr and Umar (may Allah be pleased with them) seeking knowledge regarding specific rulings and still retaining their high status as Mujtahidin.