Sayyiduna al-Aswad bin Sari' (may Allah be pleased with him) narrates: I came to the Prophet (peace and blessings be upon him) and took part in a battle with him. I obtained a zafar (perhaps a knife is meant). People were killed that day, until they even killed the children (of the enemy) (here the narrator is in doubt about the Arabic word). A man said: "O Messenger of Allah, they were only the children of the polytheists!" Then he said: "The best of you are also the children of polytheists." Then he said: "Beware, do not kill children! Beware, do not kill children! Beware, do not kill children! Every soul is born upon the fitrah (natural disposition) until it is able to speak; then its parents make it a Jew or a Christian."
Ahmad recorded it with various chains. Al-Tabarani recorded it likewise in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat, and he recorded: "News of this reached the Prophet (peace and blessings be upon him), and he said: 'What is the matter with people who went beyond limits in killing, until they even killed the children?' Then a man said:" and after that the hadith is as before. The narrators of some of Ahmad's various chains are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجهاد / 9610
Hadith Gradingمحدثین:إسنادہ صحیح
Hadith Takhrij«اخرجه ابو يعلي فى المسند (942) اخرجه الطبراني فى المعجم الكبير (829) اخرجه أحمد فى المسند (435/3) ، أخرجه مسند أحمد برقم: 15162، وأخرجه سنن الدارمي برقم: 2463، وأخرجه صحيح ابن حبان برقم: 132»