Musannaf Ibn Abi Shayba 36:388

Abu Usama narrated to us, he said: Mis'ar narrated to us, from 'Amr ibn Murrah, from al-Zuhri, who said: A man from Banu al-Du'il ibn Bakr said: "I wish I had seen the Messenger of Allah (may Allah bless him and grant him peace) and heard from him." So he said to a man: "Come with me." The man said: "I fear that Khuza'a will kill me." He continued to urge him until he went with him. Then a man from Khuza'a met him and recognized him, so he struck his stomach with a sword. He said: "I told you that they would kill me." This reached the Messenger of Allah (may Allah bless him and grant him peace), so he stood up, praised Allah and extolled Him, then said: "Indeed, Allah is the One who made Makkah sacred; people did not make it sacred. It was only made lawful for me for an hour of a day, and it is sacred thereafter. And the most hostile of people toward Allah are three: one who kills within it, or one who kills someone other than his killer, or one who seeks the blood-feuds of the Jahiliyyah—so this man has no religion." 'Amr ibn Murrah said: I narrated this hadith to Sa'id ibn al-Musayyib and said: "The most hostile (a'da) toward Allah?" He replied: "The most hostile (a'da)."