Musnad Abu Ya'la al-Mawsili 108:63

Abu Khaythama narrated to us, Sufyan narrated to us, he heard ‘Amr [narrating] from Jabir: A man entered the mosque while the Prophet, may Allah bless him and grant him peace, was delivering the sermon. He [the Prophet] said, "Have you prayed?" He said, "No." He said, "Then pray two rak'ahs."