Musannaf Ibn Abi Shayba 37:522

Mu'awiyah ibn Hisham narrated to us, he said: Sufyan narrated to us, from Isa al-Sa'di, from a man who wrote to Abu al-Bakhtari asking him about his location during the days of al-Jamajim. He said: Abu al-Bakhtari wrote back to him: "Whoever wishes, let him say [what he wants] about us. And if I knew of anything better than that which I am in, I would have come to it."