According to search-discovered classical Islamic scholarship, the principle of treating non-belligerent non-believers with equity is rooted in Quran 60:8. Tafsir scholars like Ibn Kathir and Al-Qurtubi explain this verse establishes a clear divine permission, even an encouragement, for Muslims to show kindness (birr) and act with full equity (qist) towards non-Muslims who are not hostile to the faith. The historical context (asbab al-nuzul) for this revelation was the Prophet's guidance to Asma bint Abi Bakr to maintain a kind relationship with her non-Muslim mother. The term 'birr' notably signifies a high degree of righteousness and compassion, the same word used for honoring parents. This verse serves as a cornerstone of Islamic ethics, commanding Muslims to distinguish between enemy combatants and peaceful citizens of other faiths, mandating justice and kindness as the default relationship with the latter.