Musannaf Ibn Abi Shayba 38:32

'Abdah ibn Sulayman narrated to us, from Mis'ar, from 'Amr ibn Murrah, from al-Harith ibn Juhman al-Ju'fi, who said: I truly saw us on the Day of the Camel, and our spears and their spears were intertwined, such that if a man had wished to walk upon them, he could have walked. He said: And these ones were saying, "There is no god but Allah, and Allah is the Greatest," and those ones were saying, "There is no god but Allah, and Allah is the Greatest."