Sahih al-Bukhari, Book 76, Hadith 69 (In-Book) ⓘ
Narrated Abu Huraira: I heard Allah's Messenger saying, "There is no Tiyara, and the best omen is the Fal." They asked, "What is the Fal?" He said, "A good word that one of you hears (and takes as a good omen).
حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، أَنَّ أَبَا هُرَيْرَةَ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " لاَ طِيَرَةَ، وَخَيْرُهَا الْفَأْلُ ". قَالُوا وَمَا الْفَأْلُ قَالَ " الْكَلِمَةُ الصَّالِحَةُ يَسْمَعُهَا أَحَدُكُمْ ".
also referenced under: Hadith 5754 (DarusSalam) & Volume 7, Book 71, Hadith 650 (USC-MSA)