Imam Malik's Muwatta, Chapter: Purity

Yahya related to me from Malik from Yahya ibn Said from Bushayr ibn Yasar, the mawla of the Bani Haritha, that Suwayd ibn anNuman told him that he went with the Messenger of Allah, may Allah bless him and grant him peace, on the expedition to Khaybar. When they reached as Suhba, which was near Khaybar, the Messenger of Allah, may Allah bless him and grant him peace, stopped and prayed asr. He asked for provisions but only parched barley was brought, so he asked for it to be moistened. The Messenger of Allah, may Allah bless him and grant him peace, ate and the people ate with him. Then he got up to do maghrib and rinsed his mouth out and they rinsed out theirs. Then he prayed without doing wudu.