Musnad Ahmad 1007:118

Abu Sa'id, the freed slave of Banu Hashim, narrated to us, Harb—meaning Ibn Shaddad—narrated to us, Yahya—meaning Ibn Abi Kathir—narrated to us, from 'Abdullah ibn Abi Qatadah, from his father, that the Messenger of Allah (may Allah bless him and grant him peace) said: "When one of you comes to the privy, let him not wipe himself with his right hand. And when he drinks, let him not breathe into his vessel."