غزوة خيبر
After some fighting, the Byzantine army broke contact and withdrew into the fort. At this time Khalid was fighting on foot in front of his centre. As he turned to give orders for the commencement of the siege, he saw a horseman approaching through the ranks of the Muslims. It was Abu Ubaidah ibn al-Jarrah and with him was a yellow standard and is believed to have been the standard of Muhammad at the Battle of Khaybar. This was the man who had been placed under the command of Khalid. He gave that standard to Khalid ibn al-Walid and he took it saying.