It is narrated from Sayyiduna Muti' bin al-Aswad (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said on the day of the Conquest of Makkah: "After today, no Qurayshi will be taken captive and killed without a fight."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17825