Muwatta Imam Malik (Riwayat Ibn al-Qasim)

It is narrated from the companion who performed the prayer of fear with the Messenger of Allah, peace and blessings be upon him, on the occasion of the Battle of Dhat al-Riqa'. One group formed a row with him while the other group remained facing the enemy. Then the Messenger of Allah, peace and blessings be upon him, led those who were praying with him in one rak'ah, then he remained standing and they completed the second rak'ah by themselves. Then (after saying salam) they left and formed a row facing the enemy. The other group came and performed one rak'ah with him, which was the remaining rak'ah of his prayer, then he remained seated and they completed their prayer, then he said salam with them.