The Messenger of Allah said: "The distinction between the lawful and the unlawful is the Duff and the voice."  

قَالَ رَسُولُ اللَّهِ ﷺ فَصْلُ مَا بَيْنَ الْحَرَامِ وَالْحَلاَلِ الدُّفُّ وَالصَّوْتُ قَالَ وَفِي الْبَابِ عَنْ عَائِشَةَ وَجَابِرٍ وَالرُّبَيِّعِ بِنْتِ مُعَوِّذٍ  

The Messenger of Allah said: "Publicize this marriage, and hold it in the Masjid, and beat the Duff for it."  

قَالَ رَسُولُ اللَّهِ ﷺ أَعْلِنُوا هَذَا النِّكَاحَ وَاجْعَلُوهُ فِي الْمَسَاجِدِ وَاضْرِبُوا عَلَيْهِ بِالدُّفُوفِ  

"The morning after the consummation of my marriage, the Prophet came and sat on my bed as far from me as you are sitting now, and our little girls started beating the Duff and reciting verses mourning my father who had been killed in the battle of Badr. One of them said: 'Among us is a Prophet who knows what will happen tomorrow.' On that the Prophet said: 'Stop saying this, and keep on saying what you were saying before.'"  

جَاءَ رَسُولُ اللَّهِ ﷺ فَدَخَلَ عَلَىَّ غَدَاةَ بُنِيَ بِي فَجَلَسَ عَلَى فِرَاشِي كَمَجْلِسِكَ مِنِّي وَجُوَيْرِيَاتٌ لَنَا يَضْرِبْنَ بِدُفُوفِهِنَّ وَيَنْدُبْنَ مَنْ قُتِلَ مِنْ آبَائِي يَوْمَ بَدْرٍ إِلَى أَنْ قَالَتْ إِحْدَاهُنَّ وَفِينَا نَبِيٌّ يَعْلَمُ مَا فِي غَدٍ فَقَالَ لَهَا رَسُولُ اللَّهِ ﷺ اسْكُتِي عَنْ هَذِهِ وَقُولِي الَّذِي كُنْتِ تَقُولِينَ قَبْلَهَا