Musnad Abu Ya'la al-Mawsili 159:140

'Abd al-A'la narrated to us, Hammad ibn Salamah narrated to us, from 'Ali ibn Zayd, from Aws ibn Khalid, from Abu Hurayrah, who said: The Prophet (peace be upon him) said: "The likeness of one who hears wisdom and then narrates to the worst of people what he heard is like a man who came to a shepherd and said: 'O shepherd, slaughter for me a sheep from your flock.' He said: 'Go and take the best of them by its ear.' So he went and took the ear of the sheepdog."