Narrated Thabit bin Ad-Dahhak:
who was one of the companions of the tree (those who swore allegiance to the Prophet (ﷺ) beneath the tree at Al-Hudaibiya): (DE)
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 366 (DE)
Arabic reference (DE): Book 65, Hadith 4843 (DE)