Musannaf Ibn Abi Shaybah 35343 — Those whom it is forbidden to kill

Sayyiduna al-Aswad bin Sari' (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) declared: "What is wrong with people that they went to such excess in killing that they even killed children?!" At this a man from the people spoke up: "They were only the children of the polytheists." The Messenger of Allah (peace and blessings be upon him) said: "Are not the best among you the offspring of polytheists?! Indeed, no child is born except upon the natural disposition of Islam (fitrah), until, when he reaches puberty, he expresses what is in his own heart, or his parents make him a Jew or a Christian."