Musnad Ahmad 28:450

'Abd al-Wahid al-Haddad narrated to us, Husayn al-Mu'allim and Yazid narrated to us, they said: Husayn informed us, 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) fasting while traveling and breaking his fast. And I saw him drinking while standing and while sitting. And I saw him praying barefoot and wearing sandals. And I saw him turning away [from the prayer] to his right and to his left.