The 'Hadith of the Cloak' refers to a significant tradition in Islamic thought where the Prophet Muhammad gathers his daughter Fatimah, son-in-law Ali, and grandsons Hasan and Husayn under his cloak, signifying their spiritual purity and status as the Ahl al-Bayt or the People of the House. This event underscores the special reverence and authoritative role attributed to these family members within Shia Islam, and serves as a basis for their elevated religious and social status.