Musnad Ahmad 32:1532

Ya'qub narrated to us, my father narrated to us, from Salih. Ibn Shihab said: Anas ibn Malik narrated to me, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "If the son of Adam had a valley of gold, he would love to have two valleys. And nothing will fill his mouth except dust, and Allah accepts the repentance of whoever repents."