Musnad Ahmad 30:500

'Abd al-Razzaq narrated to us, from Ma'mar, from al-Zuhri, from 'Ubayd Allah ibn 'Abd Allah ibn 'Utbah, that Abu Hurayrah said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "There is no *tiyarah* (evil omen), and the best of it is *al-fa'l* (a good omen)." It was said: O Messenger of Allah, and what is *al-fa'l*? He said: "The good word that one of you hears."