Musannaf Ibn Abi Shayba 33:64

Muhammad ibn Bishr narrated to us, he said: Mis'ar narrated to us, from Khalaf ibn Hawshab, who said: Gabriel—or he said: the angel—entered upon Joseph while he was in prison. He said: "O king, pleasant of scent, pure of garments, inform me about Jacob, or what has Jacob done?" He said: "His eyesight has gone." He said: "What has his grief reached?" He said: "The grief of seventy bereaved mothers." He said: "What is his reward?" He said: "The reward of one hundred martyrs."