To rinse the mouth after taking meals

Narrated Suwaid bin An Nu'man:

We went out with Allah's Apostle to Khaibar, and when we reached As-Sahba', the Prophet asked for food, and he was offered nothing but Sawiq. We ate, and then Allah's Apostle stood up for the prayer. He rinsed his mouth with water, and we too, rinsed our mouths. 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

حَدَّثَنَا عَلِيٌّ، حَدَّثَنَا سُفْيَانُ، سَمِعْتُ يَحْيَى بْنَ سَعِيدٍ، عَنْ بُشَيْرِ بْنِ يَسَارٍ، عَنْ سُوَيْدِ بْنِ النُّعْمَانِ، قَالَ خَرَجْنَا مَعَ رَسُولِ اللَّهِ ﷺ إِلَى خَيْبَرَ، فَلَمَّا كُنَّا بِالصَّهْبَاءِ دَعَا بِطَعَامٍ فَمَا أُتِيَ إِلاَّ بِسَوِيقٍ، فَأَكَلْنَا فَقَامَ إِلَى الصَّلاَةِ، فَتَمَضْمَضَ وَمَضْمَضْنَا.