Sunan An-Nasa'i

Jabir bin 'Abdullah narrated that:the Messenger of Allah passed by a man in the shade of a tree on whom water was being sprinkled. He said: ""What is the matter with your companion?"" They said: ""O Messenger of Allah, he is fasting."" He said: ""It is not righteousness to fast when traveling. Take to the concession which Allah has granted you, accept it