سُنَنُ النَّسَائِيِّ
Sunan an-Nasa’i 3370
The Book of Marriage
Announcing The Wedding By Singing And Beating The Duff
أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا خَالِدٌ، عَنْ شُعْبَةَ، عَنْ أَبِي بَلْجٍ، قَالَ سَمِعْتُ مُحَمَّدَ بْنَ حَاطِبٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِنَّ فَصْلَ مَا بَيْنَ الْحَلاَلِ وَالْحَرَامِ الصَّوْتُ .
It was narrated that Abu Balj said: "I heard Muhammad bin Hatib say: 'What differentiates between the lawful and the unlawful is the voice (singing).'"
Sunan an-Nasa'i, 3370hasan (Darussalam)