Abu Dawud
General Behavior
Book Number: 036 / Hadith Number: 4909
Narated By Abdullah ibn Mas'ud : Salam ibn Miskin, quoting an old man who witnessed AbuWa'il in a wedding feast, said: They began to play, amuse and sing. He united the support of his hand round his knees that were drawn up, and said: I heard Abdullah (ibn Mas'ud) say: I heard the apostle of Allah (pbuh) say: Singing produces hypocrisy in the heart.