Sahih Bukhari Volume 1, Book 4, Hadith Number 208
Narated By Suwaid bin Al-Nu’man : In the year of the conquest of Khaibar I went with Allah’s Apostle till we reached Sahba,’ a place near Khaibar, where Allah’s Apostle offered the ‘Asr prayer and asked for food. Nothing but Sawrq was brought. He ordered it to be moistened with water. He and all of us ate it and the Prophet got up for the evening prayer (Maghrib prayer), rinsed his mouth with water and we did the same, and he then prayed without repeating the ablution.