Second Generation of al-Ash`ari's Students Abu Sa`d al-Isma`ili, Isma`il ibn Ahmad ibn Ibrahim ibn Isma`il, Abu Sa`d al-Jurjani al-Shafi`i (d. 396), one of Abu Bakr al-Isma`ili's sons. Hamza ibn Yusuf al-Sahmi said in his history of Jurjan: "The imam of his time, foremost in fiqh and its usul, the Arabic language, legal pre-requisites, and kalam. He refuted al-Jassas. He formed generations of jurists from Jurjan, Tabaristan, and elsewhere. He was strictly scrupulous, generous, devoted to worship and knowledge, handsome in his appearance, courteous, and highly respected in every country. He died on the night before the day of Jum`a, in the sunset prayer, as he was reciting: 'You alone we worship and You alone we ask for help' (1:5). His funeral was attended by a throng the like of which I never saw before in Jurjan."
He was named "the Ocean son of the Ocean" in reference to his father Abu Bakr al-Isma`ili. Another of his titles is "The Greatest Shaykh" (al-shaykh al-akbar). Abu al-Tayyib al-Su`luki, Sahl ibn Muhammad ibn Sulayman al-`Ijli al-Naysaburi al-Shafi`i of the Banu Hanifa (d. 403), "the erudite imam," like his father Abu Sahl mufti of Naysabur and among its chief jurists and educators.
He took fiqh and hadith from his father, Abu al-`Abbas al-Asamm, al-Hakim, and others. From him narrated, among others, his own shaykh al-Hakim and al-Bayhaqi. Al-Hakim reported that his gathering counted five hundred inkwells. His father Abu Sahl praised his intelligence and energy and said of him: Sahlun walid - "He is a father to me" - and in his last sickness: "Sahl's absence weighs more heavily upon me than the state in which I find myself." Among Sahl al-Su`luki's sayings: "The approval of people is hard to obtain and unattainable, but Allah's approval is easily within reach and indispensible." "Whoever takes up leadership before his time undertakes his own disgrace."
Some scholars considered him the renewer of the Religion at the head of the fifth Islamic century, together with al-Baqillani and Abu Hamid al-Isfarayini. Abu Ishaq al-Isfarayini, Ibrahim ibn Muhammad ibn Ibrahim ibn Mihran, Rukn al-Din, al-Naysaburi al-Shafi`i (d. 418), the faqeeh, expert in usul, kalam, and the Arabic language, "the most unique erudite imam and teacher" according to al-Dhahabi.
He reached the rank of ijtihad. He was scrupulously pious, devoted to worship, and most trustworthy in hadith narration. He took hadith in Iraq and Khurasan from Da`laj al-Sajzi, Abu Bakr al-Shafi`i, Abu Bakr al-Isma`ili and others, and from him took al-Bayhaqi, al-Qushayri, and Abu al-Tayyib al-Tabari among others. He authored al-Jami` fi Usul al-Din wa al-Radd `ala al-Mulhidin ("The Compendium in the Principles of the Religion and the Refutation of the Atheists") and other works. A major school was built for him in Naysabur. Abu Ishaq al-Shirazi said in his Tabaqat al-Fuqaha': "The majority of the shaykhs of Naysabur took kalam and usul from him."
He was violent in his discourse against innovators. Isma`il ibn `Abbad said about the effectiveness of al-Isfarayini and his Ash`ari colleagues in debate: "Ibn al-Baqillani is a drowning sea, Ibn Furak a striking adder, al-Isfarayini a fire that burns."
Taj al-Din al-Subki narrates with a chain containing Abu Ishaq al-Isfarayini the following hadith of the Prophet: "The similitude of the believer is as the bush which the wind inclines this way and that, and the similitude of the hypocrite is as the cedar-tree that holds its ground unmoved until all of a sudden it is uprooted."
Among Abu Ishaq al-Isfarayani's contributions is his commentary on al-Shafi`i's phrase whereby "Belief cannot coexist with disbelief, while disbelief can coexist with disbelief": "If, together with belief, one holds a view such as that the world is without beginning, or other such position which negates belief, then belief is altogether annulled in that person; while disbelief, such as to assert the Trinity, if together with it one holds that Satan challenges the Merciful and wins battles over Him, as Manicheans believe, then his shirk in the Trinity is not annulled, but compounded by his Manichean shirk." Al-Subki commented: "One can infer from this that belief neither increases nor decreases, while disbelief can increase or decrease. Ponder this."
From a debate with al-Qadi `Abd al-Jabbar al-Mu`tazili: `Abd al-Jabbar: "Glory to Him Who exalted Himself above indecency!" Abu Ishaq: "Glory to Him in Whose dominion nothing befalls but what He will!" `Abd al-Jabbar: "Can our Lord will that He be disobeyed?" Abu Ishaq: "Can our Lord be disobeyed against His will?" `Abd al-Jabbar: "Do you think, if He has prevented me from being guided, that He has acted well towards me, or ill?" Abu Ishaq: "If he prevented you from something that you own, then He has acted ill towards you; but if He prevented you from something that He owns, then 'He selects for His mercy whom He will' (2:105, 3:74)." `Abd al-Jabbar remained silent.