The Prophet ﷺ said, "There is no Tiyara and the best omen is the Fal," Somebody said, "What is the Fal, O Messenger of Allah ﷺ?" He said, "A good word that one of you hears (and takes as a good omen).  

قَالَ النَّبِيُّ ﷺ لاَ طِيَرَةَ وَخَيْرُهَا الْفَأْلُ قَالَ وَمَا الْفَأْلُ يَا رَسُولَ اللَّهِ قَالَ الْكَلِمَةُ الصَّالِحَةُ يَسْمَعُهَا أَحَدُكُمْ  

The Prophet ﷺ said, "No 'Adwa (no contagious disease is conveyed to others without Allah's permission), nor Tiyara, but I like the good Fal, i.e., the good word."  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ عَدْوَى وَلاَ طِيَرَةَ وَيُعْجِبُنِي الْفَأْلُ الصَّالِحُ الْكَلِمَةُ الْحَسَنَةُ