Musannaf Ibn Abi Shayba 28:1152

Ibn Abi Bukayr narrated to us, he said: Shu’bah, from Abu al-Fayd, said: I heard Sa’id ibn Jubayr al-Ru’ayni, from his father, that he felt that Abu Bakr escorted an army, so he walked with them. He said: "Praise be to Allah, whose feet of ours have become dusty in the way of Allah." A man said: "We only escorted them." He said: "We equipped them, and we escorted them, and we prayed for them."