Amongst the Shīʿahs there are still Mujtahidūn whose Ijmāʿ is accepted, but the Sunnīs have four orthodox schools of interpretation, named after their respective founders—Ḥanafī, Shāfaʿī, Malakī, and Ḥanbalī. The Wahhābīs for the most part reject Ijmāʿ collected after the death of “the Companions.”
It will be easily understood what a fruitful source of religious dissension and sectarian strife this third foundation of the rule of faith is. Divided as the Christian Church is by its numerous sects, it will compare favourably with Muḥammadanism even in this respect. Muḥammad, it is related, prophesied that, as the Jewish Church had been divided into seventy-one sects! and the Christians into seventy-two! so his followers would be divided into seventy-three sects! But every Muslim historian is obliged to admit that they have far exceeded the limits of Muḥammad’s prophecy; for, according to ʿAbdu ʾl-Qādir al-Jīlānī, there are at least 150.
IJTIHĀD (اجتهاد). Lit. “Exertion.” The logical deduction on a legal or theological question by a Mujtahid or learned and enlightened doctor, as distinguished from Ijmāʿ, which is the collective opinion of a council of divines.
This method of attaining to a certain degree of authority in searching into the principles of jurisprudence is sanctioned by the Traditions:—
“The Prophet wished to send a man named Muʿāẕ to al-Yaman to receive some money collected for alms, which he was then to distribute to the poor. On appointing him he said: ‘O Muʿāẕ, by what rule will you act?’ He replied, ‘By the Law of the Qurʾān.’ ‘But if you find no direction therein?’ ‘Then I will act according to the Sunnah of the Prophet.’ ‘But what if that fails?’ ‘Then I will make an Ijtihād, and act on that.’ The Prophet raised his hands and said, ‘Praise be to God who guides the messenger of His Prophet in what He pleases.’ ”
The growth of this system of divinity is traced by a Sunnī writer, Mirza Qāṣim Beg, Professor in the University of St. Petersburg (extracts from which are given in Sell’s Faith of Islām), as follows:—
1. God, the only legislator, has shown the way of felicity to the people whom He has chosen, and in order to enable them to walk in that way He has shown to them the precepts which are found partly in the eternal Qurʾān, and partly in the sayings of the Prophet transmitted to posterity by the Companions and preserved in the Sunnah. That way is called the Sharīʿah (law). The rules thereof are called Aḥkām (commandments).
2. The Qurʾān and the Sunnah, which since their manifestation are the primitive sources of the orders of the Law, form two branches of study, viz. ʿIlm-i-Tafsīr, or the interpretation of the Qurʾān, and ʿIlm-i-Ḥadīs̤, or the study of Tradition.
3. All the orders of the Law have regard either to the actions (Dīn), or to the belief (Īmān) of the faithful (Mukallif).
4. As the Qurʾān and the Sunnah are the principal sources from whence the precepts of the Sharīʿah have been drawn, so the rules recognised as the principal elements of actual jurisprudence are the subject of ʿIlm-i-Fiqh, or the science of Law.