Daraqutni

Bukair bin Ashajj narrates: In Madinah Munawwarah, there were nine mosques adjacent to the blessed mosque of the Noble Prophet (peace be upon him). In the sacred era of the Noble Prophet (peace be upon him), the people living around these mosques used to hear the adhan of Sayyiduna Bilal (may Allah be pleased with him), but they would perform their prayers in these mosques. The closest among them was the mosque of Banu Amr, which belonged to Banu Najjar. There was a mosque of Banu Sa'idah, a mosque of Banu Ubaid, a mosque of Banu Salamah, a mosque of Banu Ratij, which belonged to Banu Abd al-Ashhal, a mosque of Banu Zurayq, a mosque of Banu Ghifar, a mosque of Aslam, and a mosque of Juhaynah. The narrator is doubtful about the ninth mosque.

Chapter: Whoever performs prayer facing another person, whom he sees in front of him in the direction of the qiblah, it is obligatory for him to repeat the prayer.