Principles of Islamic fiscal policy: a documentation from classical Islamic sources and contemporary scholarly perspectives

This study documents the fundamental principles of Islamic fiscal policy as would be implemented by a Caliphate State, drawing exclusively from classical Islamic sources (8th-14th century) and validated through consultation with contemporary Islamic scholars. Using a qualitative methodology combining textual analysis of primary Islamic sources (Qur'an, Hadith, and classical jurisprudential works by Abu Yousuf, Abu Obaid, Al-Mawardi, and Ibn Khaldoun) with a structured questionnaire administered to four PhD-qualified Islamic scholars, this research identifies seven core economic system pillars through preliminary validation and systematically catalogs sixteen distinct revenue sources (eight permanent, eight circumstantial) with their corresponding Sharia-based expenditure rules. This represents the first systematic integration of 8th-14th century classical documentation with 21st century scholarly validation. The findings reveal that the Caliphate State's fiscal framework differs fundamentally from contemporary systems in its ideological foundation, recognizing three ownership types (individual, public, and state), completely forbidding riba (interest/usury), prioritizing just wealth distribution, and mandating gold and silver as currency standards. The study establishes that each revenue category is governed by specific Sharia-based disbursement rules that constrain the Caliph's authority, preventing arbitrary taxation or spending. This documentation provides a theoretical foundation for future empirical research on Islamic fiscal systems and contributes to comparative economic systems literature.