Musnad Ahmad 25:1653

Rawh narrated to us, Hammad narrated to us, from Abdullah ibn Uthman ibn Khuthaym, from Sa’id ibn Jubayr, from Ibn Abbas: "That the Messenger of Allah (peace and blessings of Allah be upon him) and his companions performed Umrah from Ji’ranah. They practiced *idtiba’* (uncovering the right shoulder), and they placed their rida’s (upper garments) under their armpits and placed them over their left shoulders, then they performed *ramal* (brisk walking)."