Musnad Ahmad 1163:18

'Attab ibn Ziyad narrated to us, he said: 'Abdullah and 'Ali ibn Ishaq narrated to us, 'Abdullah informed us, he said: Ibn Lahi'ah narrated to us, he said: Bukayr narrated to me, that Kurayb, the freed slave of Ibn 'Abbas, narrated to him that he heard Maymunah, the wife of the Prophet, may Allah bless him and grant him peace, saying: "The Messenger of Allah, may Allah bless him and grant him peace, ate from a shoulder [of a sheep], then he stood and prayed, and he did not perform ablution."