Musnad Ahmad 26:742

'Abd al-Razzaq narrated to us, Isra'il informed us, from Simak, from 'Abd al-Rahman ibn 'Abd Allah, from his father, who said: The Prophet, peace and blessings of Allah be upon him, said: "Whoever assists his people in injustice is like a camel that falls into a pit and is being pulled by its tail."