Musnad Ahmad 25:880

Sulayman ibn Dawud narrated to us, Hisham—meaning al-Dastawa'i—narrated to us, from Ayyub, from Ikrimah, from Ibn Abbas, that the Prophet, peace and blessings of Allah be upon him, said: "Do not boast about your fathers who died in the Jahiliyyah (pre-Islamic period). For by the One in Whose hand is my soul, the dung beetle rolling its dung with its nose is better than your fathers who died in the Jahiliyyah."