Sahih Bukhari Volume 7, Book 70, Hadith 5392

حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا حَمَّادٌ، عَنْ يَحْيَى، عَنْ بُشَيْرِ بْنِ يَسَارٍ، عَنْ سُوَيْدِ بْنِ النُّعْمَانِ، أَنَّهُ أَخْبَرَهُ أَنَّهُمْ، كَانُوا مَعَ النَّبِيِّ صلى الله عليه وسلم بِالصَّهْبَاءِ ـ وَهْىَ عَلَى رَوْحَةٍ مِنْ خَيْبَرَ ـ فَحَضَرَتِ الصَّلاَةُ، فَدَعَا بِطَعَامٍ فَلَمْ يَجِدْهُ إِلاَّ سَوِيقًا، فَلاَكَ مِنْهُ فَلُكْنَا مَعَهُ، ثُمَّ دَعَا بِمَاءٍ فَمَضْمَضَ، ثُمَّ صَلَّى وَصَلَّيْنَا، وَلَمْ يَتَوَضَّأْ‏.‏

Narrated By Suwaid bin An-Nu'man : That while they were with the Prophet at As-Sahba' which was at a distance of one day's journey from Khaibar the prayer became due, and the Prophet asked the people for food but there was nothing with the people except Sawiq. He ate of it and we ate along with him, and then he asked for water and rinsed his mouth (with it), and then offered the (Maghrib) prayer and we too offered the prayer but the Prophet did not perform ablution (again after eating the Sawiq.).