Musnad Ahmad 25:711

Muhammad ibn Ja‘far narrated to us, Ibn Jurayj narrated to us, Sa‘id ibn al-Huwayrith narrated to me, from Ibn ‘Abbas, who said: "The Messenger of Allah (ﷺ) went out to relieve himself, then he returned. A piece of meat was brought to him, and he did not perform ablution, then he ate from it." ‘Amr ibn ‘Ali added in this hadith, from Sa‘id ibn al-Huwayrith, that he said: "It was said, 'O Messenger of Allah, you did not perform ablution.' He said: 'I did not intend to pray so that I should perform ablution.'"