Musannaf Ibn Abi Shayba 28:589

Waki' narrated to us, he said: Sufyan narrated to us, from Abu al-Zinad, from al-Muraqqa' ibn 'Abd Allah ibn Sayfi, from Hanzala al-Katib, he said: We went on a military expedition with the Prophet, may Allah bless him and grant him peace, and we passed by a killed woman, and the people had gathered around her. He said: So they cleared the way for him. He said: "This one was not fighting among those who fight." Then he said to a man: "Go to Khalid ibn al-Walid and say to him: 'The Messenger of Allah, may Allah bless him and grant him peace, commands you, saying: Do not kill offspring, nor a hired laborer.'"