Scholarly Reception and Influence on Later Usul al-Fiqh

Al-Mustasfa achieved immediate recognition as one of the masterworks of Islamic legal theory. Al-Ghazali's extraordinary reputation, combined with the genuine philosophical depth and organizational sophistication of the work, ensured that it would be studied by scholars of every subsequent generation and every legal school.

Among its most direct influences was its role as the model for Ibn Qudamah's Rawdat an-Nadhir — a testimony from the Hanbali tradition to al-Ghazali's achievement. Ibn Qudamah borrowed al-Ghazali's organizational framework and much of his analytical vocabulary while adapting the substantive positions to the Hanbali school, demonstrating that Al-Mustasfa had created an architecture for usul al-fiqh that transcended any single school.

Ar-Razi (d. 606 AH/1210 CE), the great Ash'ari theologian and Shafi'i jurist, engaged extensively with Al-Mustasfa in his own usul work Al-Mahsul, which built on and in some respects transcended al-Ghazali's achievement while acknowledging his predecessor's foundational contribution. Al-Amidi (d. 631 AH/1233 CE) similarly developed the tradition inaugurated by Al-Mustasfa in his Al-Ihkam fi Usul al-Ahkam.

Ash-Shatibi (d. 790 AH/1388 CE), the great Maliki legal theorist, took al-Ghazali's treatment of the maqasid ash-Shariah as a starting point for his much more extensive development of maqasid theory in Al-Muwafaqat. The maqasid framework has become one of the most discussed concepts in contemporary Islamic legal scholarship, and its classical roots in Al-Mustasfa are widely acknowledged.

In modern Islamic scholarship, Al-Mustasfa has attracted significant academic attention. Mohammad Hashim Kamali's Principles of Islamic Jurisprudence, one of the most widely used English-language introductions to usul al-fiqh, draws extensively on al-Ghazali's framework. Wael Hallaq's history of Islamic legal theory treats Al-Mustasfa as a pivotal text in the development of the discipline. These modern engagements confirm the work's continuing relevance for both traditional Islamic education and academic Islamic studies. The enduring power of Al-Mustasfa lies in the universality of the questions it addresses: how should a community derive law from texts that do not address every situation? How should reason and revelation be balanced when they appear to conflict? How can law serve human welfare without becoming merely a tool of human preference? These are perennial questions, and al-Ghazali's rigorous engagement with them in Al-Mustasfa remains among the most penetrating treatments the Islamic tradition has produced.