Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

that his father said: "We used to perform prayer while the beasts were passing in front of us. That was mentioned to the Messenger of Allah (saw) and he said: 'If something like the hand of a saddle* is placed in front of anyone of you, it will not matter whoever passes in front of him." (Sahih) *It is the piece of wood on the camel saddle which is held on to. (Explanation by Sindi)