Hadithcore
Sahih al-Bukhari, 4164
sahih

Narrated Sa`id bin Al-Musaiyab:

That his father was amongst those who had given the Pledge of allegiance (to the Prophet (ﷺ) ) beneath the Tree, and the next year when they went towards the Tree, they were not able to recognize it.

حَدَّثَنَا مُوسَى، حَدَّثَنَا أَبُو عَوَانَةَ، حَدَّثَنَا طَارِقٌ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِيهِ، أَنَّهُ كَانَ مِمَّنْ بَايَعَ تَحْتَ الشَّجَرَةِ، فَرَجَعْنَا إِلَيْهَا الْعَامَ الْمُقْبِلَ فَعَمِيَتْ عَلَيْنَا‏.‏

References2 variants
In-Book Reference
Book 64, Hadith 206
USC-MSA web (English) reference
Vol. 5, Book 59, Hadith 482 (deprecated numbering scheme)