Musannaf Ibn Abi Shayba 3:5899

Ghundar narrated to us, from Shu'bah, from al-Hakam, from Yazid al-Faqir, from Jabir ibn 'Abd Allah, that the Messenger of Allah (may Allah bless him and grant him peace) prayed the prayer of fear with them. A row stood in front of him and a row stood behind him. He prayed with them, and those [in the back] came until they stood in the place of those [in the front]. The Messenger of Allah (may Allah bless him and grant him peace) prayed one rak'ah and two prostrations with them, then he performed the taslim. Thus, there were two rak'ahs for the Prophet (may Allah bless him and grant him peace), and one rak'ah each for them.