Hadith 629:4
'Affan narrated to us, Abu 'Awanah narrated to us, Abu Balj narrated to us, from Muhammad ibn Hatib, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The distinction between the lawful and the unlawful is the voice and the beating of the duff (hand drum)."
حدثنا عفان، حدثنا أبو عوانة، حدثنا أبو بلج، عن محمد بن حاطب، قال: قال رسول الله صلى الله عليه وسلم: " فصل ما بين الحلال والحرام، الصوت وضرب الدف "