Sahih Bukhari Volume 005, Book 058, Hadith Number 268.

Narated By 'Aisha : That once Abu Bakr came to her on the day of 'Id-ul-Fitr or 'Id ul Adha while the Prophet was with her and there were two girl singers with her, singing songs of the Ansar about the day of Buath. Abu Bakr said twice. "Musical instrument of Satan!" But the Prophet said, "Leave them Abu Bakr, for every nation has an 'Id (i.e. festival) and this day is our 'Id."