(72) باب إِعْلاَنِ النِّكَاحِ بِالصَّوْتِ وَضَرْبِ الدُّفِّ .
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).'" (ID)
Reference (ID): Sunan an-Nasa'i 3370 (ID)
In-book reference (ID): Book 26, Hadith 175 (ID)
English translation (ID): Vol. 4, Book 26, Hadith 3372 (ID)