Musnad Ahmad 943:3

'Abd al-Rahman ibn Mahdi narrated to us, Hammad ibn Salamah narrated to us, from 'Aqil ibn Talhah, from Muslim ibn Haytham, from al-Ash'ath ibn Qays, who said: I came to the Messenger of Allah (peace and blessings of Allah be upon him) with a delegation, and they did not consider me the best of them. I said: "O Messenger of Allah, we claim that you are from us." He said: "We are the sons of al-Nadr ibn Kinanah; we do not disavow our mother, nor do we deny our father." Al-Ash'ath used to say: "I will not be brought a man who denies that Quraysh are from al-Nadr ibn Kinanah, except that I will flog him with the prescribed punishment."