Musnad Ahmad 25:1401

Muhammad ibn Bakr narrated to us, Ibn Jurayj informed us, he said: Sa'id ibn al-Huwayrith informed me that he heard Ibn Abbas saying: "The Messenger of Allah (may Allah bless him and grant him peace) went out to relieve himself, so he fulfilled his need in the privy. Then he came, and food was brought near to him, so he ate and did not touch water."