Musnad Ahmad 32:130

'Abd al-Rahman narrated to us, Sulaym ibn Hayyan narrated to us, from Qatadah, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, in Paradise there is a tree in whose shade a rider travels for one hundred years, and he does not cross it." He said: So I narrated it to my father, and he said: I heard Abu Hurayrah narrating it.