Musnad Ahmad 31:887

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from 'Ubayd Allah, and 'Abd al-A'la narrated from Ma'mar, from al-Zuhri, and 'Abd al-A'la said, from 'Ata' ibn Yazid, from Abu Sa'id al-Khudri, who said: "The Messenger of Allah (may Allah bless him and grant him peace) forbade the turning of the mouths of water skins (to drink directly from them)."