Musnad Ahmad 33:832

Abu al-Jawwab narrated to us, Ammar ibn Ruzayq narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) prepared an army one night until half the night had passed, or it reached that point. Then he came out and said: "The people have prayed and slept, while you have been waiting for this prayer. Know that you will remain in a state of prayer as long as you are waiting for it."