According to search-discovered classical Islamic scholarship, the etiquette of entering homes, known as Adab al-Isti'dhan, is a foundational principle of social conduct mandated in Surah An-Nur, verses 27-28. Ibn Kathir explains these verses were a divine reform from pre-Islamic practices, establishing the sanctity and privacy of the home. The protocol involves three core components: seeking permission (Isti'dhan), offering the greeting of peace (Salam), and respecting the inhabitants' right to refuse entry. Al-Qurtubi emphasizes the juridical obligation of this act, highlighting that if one is asked to 'go back', they must do so without resentment, as this is 'purer' for them. The linguistic choice of 'tasta'nisu' (seeking familiarity) over simply 'tasta'dhinu' (seeking permission) in verse 27 suggests the goal is not just mechanical permission but ensuring a warm and welcome entry. This synthesis establishes a comprehensive social ethic that prioritizes privacy, respect, and mutual comfort, forming a cornerstone of Islamic communal life.