Musnad Ahmad 403:8

Abdullah ibn Ahmad said: Muhammad ibn Abi Bakr narrated to us, he said: Hammad narrated to us, he narrated: ‘Amr, from Ibn Abbas, from al-Sa’b ibn Jaththama, who said: It was said: "O Messenger of Allah, our horses have trampled the children of the polytheists." The Messenger of Allah, peace and blessings of Allah be upon him, said: "They are from their fathers."