Musnad Ahmad 25:1594

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from Zayd ibn Aslam, from 'Ata' ibn Yasar, that he heard Ibn 'Abbas saying: "The Prophet, peace and blessings of Allah be upon him, performed ablution, then he cut a piece from a shoulder [of meat] and ate, then he went to the prayer and did not perform ablution."