He replied: I shall judge in accordance with Allah's Book. He asked: (What will you do) if you do not find any guidance in Allah's Book? He replied: (I shall act) in accordance with the Sunnah of the Messenger of Allah (ﷺ).
He asked: (What will you do) if you do not find any guidance in the Sunnah of the Messenger of Allah (ﷺ) and in Allah's Book?
He replied: I shall do my best to form an opinion and I shall spare no effort.
The Messenger of Allah (ﷺ) then patted him on the breast and said: Praise be to Allah Who has helped the messenger of the Messenger of Allah to find something which pleases the Messenger of Allah.
The Office of the Judge (Kitab Al-Aqdiyah)
Sunan Abi Dawud 3592 - Classical Tafsir by Imam Ibn al-Qayyim al-Jawziyyah
Primary Sources of Islamic Judgement
The hadith establishes the fundamental hierarchy for Islamic judicial decision-making. First, the Quran serves as the primary source, being the direct revelation from Allah. When no explicit ruling is found therein, the judge must turn to the Sunnah of the Prophet Muhammad (ﷺ), which explains and elaborates upon the Quran.
The Process of Ijtihad
When both Quran and Sunnah provide no direct guidance, the judge must exercise ijtihad (independent legal reasoning). This involves thorough examination of the case, consideration of legal principles, analogy (qiyas) to established rulings, and consultation of scholarly consensus where applicable.
The phrase "I shall spare no effort" indicates that ijtihad requires exhaustive research and sincere dedication. The judge must utilize all available Islamic legal tools while maintaining piety and fear of Allah in the process.
Divine Approval of Sound Methodology
The Prophet's (ﷺ) physical gesture of patting Mu'adh's breast coupled with his praise demonstrates Allah's approval of this systematic approach to judgment. This indicates that a judge who follows this methodology, even if he errs in his conclusion, receives one reward for his sincere effort.
This hadith establishes the legitimacy of scholarly reasoning within Islamic law while maintaining the supremacy of divine revelation, creating a balanced system that can address new situations while remaining rooted in sacred texts.