that the Prophet said: “Announce this marriage, and beat the sieve for it.”  

عَنِ النَّبِيِّ ﷺ قَالَ أَعْلِنُوا هَذَا النِّكَاحَ وَاضْرِبُوا عَلَيْهِ بِالْغِرْبَالِ  

“What differentiates between the lawful and the unlawful is (beating) the Daff and raising the voices (in song) at the time of marriage.”  

قَالَ رَسُولُ اللَّهِ ﷺ فَصْلُ مَا بَيْنَ الْحَلاَلِ وَالْحَرَامِ الدُّفُّ وَالصَّوْتُ فِي النِّكَاحِ