From Ibn ‘Umar who said: The Messenger of Allah (SAW) came back from defecating; and a man met Him at Bi’r Jamal and greeted Him, but the Messenger of Allah (SAW) did not respond to him until He came to a wall. He put his hand on the wall and then wiped his face and his hands, and then the Messenger of Allah (SAW) returned the greeting to the man.