Musnad Ahmad 30:2139

'Affan narrated to us, 'Abd al-Wahid ibn Ziyad narrated to us, he said: Ma'mar narrated to us, from al-Zuhri, from Humayd ibn 'Abd al-Rahman, from Abu Hurayrah, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no *tiyarah* (evil omen), and the best of it is *al-fa'l* (a good omen)." They said: O Messenger of Allah, and what is *al-fa'l*? He said: "The righteous word that one of you hears."