Musannaf Ibn Abi Shayba 9:504

Ghundar narrated to us, from Shu'bah, who said: I heard Abu Ishaq narrating from 'Amr ibn Rabi'ah that he said: I was with Thabit ibn Wadi'ah and Qurzah ibn Ka'b at a wedding, and I heard the sound of singing. I said, "Do you not hear?" They said, "It has been permitted for us [to engage in] singing at a wedding, and weeping over the dead without wailing."