Musannaf Ibn Abi Shayba 3:4285

Abu Khalid al-Ahmar narrated to us, from al-Dahhak ibn Uthman, from Nafi’, that Ibn Umar was occupied with a building of his, so he prayed Dhuhr. Then he passed by the mosque of Banu ‘Awf while they were praying, so he prayed with them.