Sayyiduna Sa'b bin Jaththamah (may Allah be pleased with him) said: O Messenger of Allah, in the confusion of the attack the horses strike some of the offspring of the polytheists (so what is the ruling)? The Messenger of Allah (peace and blessings be upon him) said: "They are also of them" - or he said: "They are with their fathers."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7421