Al-Masjid al-Nabawi in the Prophet’s time was not merely a place of worship for Muslims; it functioned as a multi-purpose institution for guidance, social engagement, interfaith dialogue, and the governance of the emerging Islamic polity. One of the most striking manifestations of this role is the Prophetic practice in responding to the presence of non-Muslims within the mosque. Employing a historical-analytical approach and drawing on primary sources of early Islamic history and sīrah, this study addresses the following question: How did the Prophetic practice employ al-Masjid al-Nabawi as a focal point for guidance and for the cultural–political engagement of non-Muslims? The findings indicate that, through a deliberate and guidance-oriented policy, the Prophet (peace be upon him) managed the presence of polytheists, People of the Book, and tribal delegations in the mosque, using this space as a platform for invitation to Islam, dialogue, the communication of the Islamic message, and the consolidation of political order. This practice reached its height in the ninth year after the Hijrah, known as the “Year of Delegations” (ʿĀm al-Wufūd), when dozens of delegations from various tribes and groups entered the Prophet’s Mosque: many embraced Islam, while others, maintaining their faith, remained within frameworks of security and peaceful coexistence. These historical indications suggest that, in the Prophetic model, al-Masjid al-Nabawi became an active bridge between Islam and non-Muslims, playing a fundamental role in the spread, consolidation, and institutionalization of the Islamic community and polity.