Musnad Ahmad 30:1900

'Affan narrated to us, Abu 'Awanah narrated to us, from 'Umar ibn Abi Salamah, from his father, from Abu Hurairah, who said: It was said, "O Messenger of Allah, what is *at-tiyarah* (ill-omen/superstition)?" He said, "There is no *ta'ir* (ill-omen)," three times. And he said, "The best of *al-fa'l* (optimistic omen) is the good word."