Narrated Tariq: (The tree where the Ridwan Pledge of allegiance was taken by the Prophet) was mentioned before Said bin AlMusaiyab. On that he smiled and said, "My father informed me (about it) and he had witnessed it (i.e. the Pledge) ."
— Sahih Bukhari, Volume 5, Book 59: Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi), Hadith #483