Sunan Ibn Majah Book 5, Hadith 137
“Allahu Akbar, Allahu Akbar, Ashhadu an la
ilaha
illallah, Ashhadu anna Muhammadan Rasulullah (Allah is the Most
Great,
Allah is Most Great, I bear witness that none has the right to
be
worshipped but Allah, I bear witness that Muhammad is the
Messenger of
Allah).” Then he (Ibn ‘Abbas) said: “Proclaim to
the people that they
should pray in their houses.” The people said
to him: “What is this
that you have done?” He said: “One who is
better than me did that. Are
you telling me that I should bring the
people out of their houses and
make them come to me wading through
the mud up to their knees?”
“Perform your prayer at your camps.”
“We used to perform prayer while the beasts were passing in front of us. That was mentioned to the Messenger of Allah (ﷺ) 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.”
* It is the piece of wood on the camel saddle which is held on to (to climb onto the camel).