The Book of Marriage
26/72. Chapter:
Announcing The Wedding By Singing And Beating The Duff
Sunan an-Nasai
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).'"
Reference : Sunan an-Nasa'i 3370In-book reference : Book 26, Hadith 175English translation : Vol. 4, Book 26, Hadith 3372