Musnad Abu Ya'la al-Mawsili 115:302

Ubayd Allah narrated to us, Harami narrated to us, Shu'bah narrated to us, from Qatadah, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) said: "If the son of Adam had a valley of wealth, he would seek a second one to go with it. And if he had a second, he would seek a third to go with it. And nothing fills the belly of the son of Adam except dust, and Allah turns in forgiveness to whoever repents." He (the narrator) said: "I do not know if it is something Allah revealed or if he was saying it."