Al-Juwayni

Dhia' ul-Dīn 'Abd al-Malik ibn Yūsuf al-Juwaynī al-Shafi'ī (, 17 February 1028— 19 August 1085; 419—478 AH) was a Persian Sunni Shafi'i jurist and mutakallim theologian. His name is commonly abbreviated as Al-Juwayni; he is also commonly referred to as "Imam al Haramayn", meaning "leading master of the two holy cities", that is, Mecca and Medina.
Biography.
Al-Juwayni was born on 17 February 1028 in a village on the outskirts of Naysabur called Bushtaniqan in Iran, Al-Juwayni was a prominent Muslim scholar known for his gifted intellect in Islamic legal matters. Al-Juwayni was born into a family of legal study. His father, Abu Muhammad 'Abdallah b. Yusef al-Juwayni, was a well-known master of Law in the Shafi′i community as well as a Shafi'i teacher and his older brother, Abu'l-Hasan 'Ali al-Juwayni, was a Sufi teacher of Hadith.
Al-Juwayni grew up in Naysabur, an intellectually thriving area drawing scholars to it. Naturally, Juwayni did not have to search far for his education. At the time, the teachings of the Shafi'i school were closely linked to the Ash'arite theology which al-Juwayni decided to study for several years after the death of his father, though he would later regret the time he invested in studying and debating the school's principles while on his deathbed. He took over for his father at this point and began his teaching career at only 19 years of age.
The Seljuks, at the time, were moving quickly in their conquest of eastern Iran and Tughril Beg became the first sultan. Tughril Beg was a Mutazili-Hanafi adherent and at the time, the Ash'arite theological camp and the Hanafi school of legal thought shared a hostile relationship based in differences of opinion regarding doctrine and when Tughril Beg was named wazir in Nishapur, he forbid al-Juwayni to practice or teach the Ash'ari theological perspective.
Al-Juwayni traveled to Mecca and Medina in search of an interim home. He taught and studied there in Hijaz for four years. During this time, al-Juwayni became hugely popularized because of his father's prominence in the scholarly world, and his exile. He gained a large following and was invited back to Nishapur by the founder of the Shafii Madrasa, Khwaja Nizam al-Mulk. Upon his return, Juwayni was appointed to teach the doctrine of the Ash'arites at the Nizamiyya Madrasa until he died in 1085CE (which would turn out to be about 26 years). Al-Juwayni spent his life studying and producing influential treatises in Muslim government; it is suspected that most of his works (below) came out of this period after his return from Mecca and Medina.
Al-Juwayni was the teacher of one of the most influential scholars in the Islamic tradition, particularly Sufism, al-Ghazali.
Doctrine.
Al-Juwayni, a Sunni jurist and Mutakallim, or scholar engaged in the study of theological principles, spent his life deciphering between what a Muslim ought and ought not to do. He was said to be stubborn and accepting of any legal speculation whatsoever. His basic principle was that the law should not be left to speculation on any grounds. Rather, texts hold the answers to any possible legal debate in some capacity or another. He was a master of the Koran and Hadith texts in addition to being well versed in the particular school of Shafi'i and theological practices of the Ash'arite persuasion.
Works.
Al-Juwayni's primary work "Kitab Al-Irshad Ila Qawati' Al-Adilla Fi Usul al-I'tiqad" (), his "guidebook to conclusive proofs for the principles of belief" helps to illustrate his doctrine. It is intended to outline exactly "what has" been proven, "what can" be proven and "how" those things can be proven. He focuses much of his attention on God and the fundamental Islamic principle that God is the only and all-powerful creator. He explains that we are often caught up in a temporally contingent existence, lost in continuity but that we should realize God's ability to interrupt this continuity at any time. Al-Juwayni focuses a similar amount of attention on legal methodology and is particularly concerned with the methods for discerning difficult debates. He explains abrogation, for example, in great detail.
In fiqh, uṣūl, kalām
The book Fara'id al-Simtayn is sometimes mistakenly thought to be authored by the Sunni Abd'al Malik al-Juwayni. It was in fact authored by another Sunni scholar Ibrahim bin Muhammad bin Himaway al Juwayni who died in 1322 AD (722 A.H.)