Sahih Bukhari Volume 5, Book 59, Hadith Number 486.

Narrated By Iyas bin Salama bin Al-Akwa : My father who was amongst those who had given the Pledge of allegiance to the Prophet beneath the Tree, said to me, “We used to offer the Jumua prayer with the Prophet and then depart at a time when the walls had no shade for us to take shelter in.”