Musnad Ahmad 28:543

'Abd al-Wahhab narrated to us, Sa'id narrated to us, from Husayn al-Mu'allim—'Abd al-Wahhab said: "And I heard it from him, meaning Husayn"—from 'Amr ibn Shu'ayb, from his father, from his grandfather, who said: I saw the Messenger of Allah (may Allah bless him and grant him peace) turning away from his right and from his left [after prayer]. And I saw him praying barefoot and wearing sandals. And I saw him fasting while traveling and breaking his fast. And I saw him drinking while sitting and while standing.