Musnad Ahmad 33:321

Yahya narrated to us, from ‘Abd al-Malik, ‘Ata’ narrated to me, from Jabir ibn ‘Abd Allah, that he prayed the Fear Prayer with the Messenger of Allah (may Allah bless him and grant him peace). He mentioned that the enemy was between him and the Qiblah, and that we formed two rows behind him. He said the Takbir, and we all said the Takbir with him. Then he bowed, and we all bowed with him. When he raised his head from bowing, he prostrated, and the row that was behind him prostrated with him, while the rear row stood facing the enemy. When he stood up, and the row that was behind him stood with him, the rear row went down to prostrate. Then the rear row moved forward, and the front row moved backward. Then he bowed, and we all bowed with him. Then he prostrated, and the row that was behind him prostrated with him. When the row that was behind him prostrated and sat, the rear row went down to prostrate. Then he said the Taslim, and we all said the Taslim with him. Jabir said: "Just as these guards of yours do with their commanders."