Musnad Ahmad 30:2742

Muhammad ibn Ja’far and Hajjaj narrated to us, they said: Shu’bah narrated to us, he said: I heard Abu al-Dahhak narrating from Abu Hurairah, from the Prophet, may Allah bless him and grant him peace, that he said: "Indeed, in Paradise there is a tree in whose shade a rider travels for seventy—or one hundred—years; it is the Tree of Eternity." Hajjaj said: "Or one hundred years, the Tree of Eternity." I said to Shu’bah: "Is it the Tree of Eternity?" He said: "It is not in it, it is [just] the tree."