Sayyiduna Sa'b bin Jaththamah (may Allah be pleased with him) said: I asked the Messenger of Allah (peace and blessings be upon him) about the children in the houses of the polytheists, which we attack at night: what is the ruling on the children who come under the attack? He (peace and blessings be upon him) said: "They are also of them."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7423