"The Messenger of Allah said: 'What differentiates between the lawful and the unlawful is the Duff, and the voice (singing) for the wedding.'"  

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

"I heard Muhammad bin Hatib say: 'What differentiates between the lawful and the unlawful is the voice (singing).'"  

قَالَ رَسُولُ اللَّهِ ﷺ إِنَّ فَصْلَ مَا بَيْنَ الْحَلاَلِ وَالْحَرَامِ الصَّوْتُ