Musannaf Ibn Abi Shayba 3:5788

Waki' narrated to us, he said: Sufyan and Ibn Abi Layla narrated to us, from 'Awn ibn Abi Juhayfah al-Suwa'i, from his father, who said: I prayed the Dhuhr prayer with the Prophet, may Allah bless him and grant him peace, at Mina, two rak'ahs. Then we did not cease to pray two rak'ahs until he returned to Medina.