Musnad Ahmad 30:1635

'Abd al-Samad narrated to us, Hammad narrated to us, from Wasil, from Yahya ibn 'Aqil, from Abu Hurayrah, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Retribution will be taken for the creatures from one another, even for the hornless sheep from the horned one, and even for the ant from the ant."