Musnad Ahmad 907:48

Aswad ibn Amir narrated to us, Sharik narrated to us, from Simak, from Jabir ibn Samurah, who said: "I witnessed the Prophet, peace and blessings of Allah be upon him, more than a hundred times in the mosque, while his companions were reciting poetry and discussing things from the affairs of the Jahiliyyah (pre-Islamic era), and he would sometimes smile with them."