Sahih al-Bukhari, Volume 5, Book 59, Hadith 492 (USC-MSA) ⓘ
Narrated Suwaid bin An-Nu`man: who was one of those who witnessed (the Pledge of allegiance beneath) the Tree: Allah's Messenger and his companions were given Sawiq and they chewed it.
حَدَّثَنِي مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ شُعْبَةَ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ بُشَيْرِ بْنِ يَسَارٍ، عَنْ سُوَيْدِ بْنِ النُّعْمَانِ ـ وَكَانَ مِنْ أَصْحَابِ الشَّجَرَةِ ـ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَأَصْحَابُهُ أُتُوا بِسَوِيقٍ فَلاَكُوهُ. تَابَعَهُ مُعَاذٌ عَنْ شُعْبَةَ.
also referenced under: Book 64, Hadith 217 (In-Book) & Hadith 4175 (DarusSalam)