Musnad Ahmad 32:128

'Abd al-Rahman ibn Mahdi narrated to us, Malik narrated to us, from al-Zuhri, from Anas, that the Messenger of Allah (peace and blessings of Allah be upon him) entered Makkah on the day of the Conquest, and he was wearing a helmet. It was said to him: "Ibn Khatal is clinging to the curtains of the Ka'bah." The Prophet (peace and blessings of Allah be upon him) said: "Kill him." 'Abd al-Rahman said: And in what I read to him—meaning Malik—he said: "And the Prophet (peace and blessings of Allah be upon him) was not in a state of ihram on that day, and Allah knows best."