Borobudur Law and Society Journal

Sharia financial innovation in Indonesia, from digital banking services to the productive use of zakat, regularly produces transactions that the Qur’an and Sunnah do not regulate in detail. This study analyses the relevance of four supplementary methods of Islamic legal reasoning, istihsan, istishab, maslahah mursalah and ‘urf, in responding to such innovation. It is normative legal research that uses conceptual and statutory approaches and analyses classical and modern works on usul al-fiqh, the statutes on sharia banking and zakat and the fatwas of the National Sharia Board of the Indonesian Council of Ulama (DSN-MUI) on istishna’, electronic money and technology-based financing. The analysis shows that the four methods are not interchangeable: each has its own ground, conditions and limit, and each answers a different question, namely whether an exception to a general rule is justified, which starting presumption applies, whether a measure serves a genuine public interest, and whether a prevailing practice may be recognised. The fatwas examined invoke benefit and public interest openly but do not name the other methods, so the link between method and fatwa is an analytical reconstruction. The study concludes that the methods remain relevant only as disciplined reasoning, subordinate to the texts, the fatwa authority and positive law, and recommends that fatwa reasoning be stated more explicitly.