Musnad Ahmad 32:1554

Hassan narrated to us, Shaiban narrated to us, from Qatadah, from Anas ibn Malik, who said: I heard the Prophet of Allah, peace and blessings of Allah be upon him, say: "If the son of Adam had two valleys of wealth, he would seek a third valley. And nothing fills the belly of the son of Adam except dust. And Allah accepts the repentance of whoever repents."