Musnad Ahmad 1034:189

Bahz narrated to us, Abu 'Awanah narrated to us, Qatadah narrated to us, from Nasr ibn 'Asim, from Subay' ibn Khalid, who said: I arrived in Kufa at the time Tustar was conquered. He then mentioned the like of the meaning of the hadith of Ma'mar, and he said: "His burden was cast off."