Sahih al-Bukhari, Volume 5, Book 59, Hadith 491 (USC-MSA) ⓘ

Narrated Zahir Al-Aslami: (who was one of those who had witnessed (the Pledge of allegiance beneath) the Tree) While I was making fire beneath the cooking pots containing donkey's meat, the announcer of Allah's Messenger announced, "Allah's Messenger forbids you to eat donkey's meat."

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ، حَدَّثَنَا أَبُو عَامِرٍ، حَدَّثَنَا إِسْرَائِيلُ، عَنْ مَجْزَأَةَ بْنِ زَاهِرٍ الأَسْلَمِيِّ، عَنْ أَبِيهِ ـ وَكَانَ مِمَّنْ شَهِدَ الشَّجَرَةَ ـ قَالَ إِنِّي لأُوقِدُ تَحْتَ الْقِدْرِ بِلُحُومِ الْحُمُرِ إِذْ نَادَى مُنَادِي رَسُولِ اللَّهِ صلى الله عليه وسلم إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم يَنْهَاكُمْ عَنْ لُحُومِ الْحُمُرِ‏.‏

The same narration was told by Majzaa from a man called Uhban bin Aus who was one of those who had witnessed (the Pledge of allegiance beneath) the Tree., and who had some trouble in his knee so that while doing prostrations, he used to put a pillow underneath his knee.

وَعَنْ مَجْزَأَةَ، عَنْ رَجُلٍ، مِنْهُمْ مِنْ أَصْحَابِ الشَّجَرَةِ اسْمُهُ أُهْبَانُ بْنُ أَوْسٍ وَكَانَ اشْتَكَى رُكْبَتَهُ، وَكَانَ إِذَا سَجَدَ جَعَلَ تَحْتَ رُكْبَتِهِ وِسَادَةً‏.‏