Sahih Bukhari Volume 7, Book 70, Hadith 5457

قَالَ يَحْيَى سَمِعْتُ بُشَيْرًا، يَقُولُ حَدَّثَنَا سُوَيْدٌ، خَرَجْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم إِلَى خَيْبَرَ، فَلَمَّا كُنَّا بِالصَّهْبَاءِ ـ قَالَ يَحْيَى وَهْىَ مِنْ خَيْبَرَ عَلَى رَوْحَةٍ ـ دَعَا بِطَعَامٍ فَمَا أُتِيَ إِلاَّ بِسَوِيقٍ، فَلُكْنَاهُ فَأَكَلْنَا مَعَهُ، ثُمَّ دَعَا بِمَاءٍ فَمَضْمَضَ وَمَضْمَضْنَا مَعَهُ، ثُمَّ صَلَّى بِنَا الْمَغْرِبَ وَلَمْ يَتَوَضَّأْ‏.‏ وَقَالَ سُفْيَانُ كَأَنَّكَ تَسْمَعُهُ مِنْ يَحْيَى‏

Narrated Suwaid; We went out with Allah's Apostle to Khaibar. and when we reached As-Sahba', which (Yahya says) is one day' journey from Khaibar, the Prophet asked for food, and he was offered nothing but Sawiq which we chewed and ate. Then the Prophet asked for water and rinsed his mouth, and we too, rinsed our mouths along with him. He then led us in the Maghrib prayer without performing ablution again.