Musnad Ahmad 507:0

Narrated Abu Juhaim bin al-Harith bin as-Simmah: The Messenger of Allah (ﷺ) came from the direction of Bi'r Jamal. A man met him and greeted him with peace (salam), but the Messenger of Allah (ﷺ) did not return the greeting to him. Then the Messenger of Allah (ﷺ) turned toward the wall, wiped his face and his hands, and then returned the greeting to the man.