It was narrated from Jabir bin 'Abdullah that: the Messenger of Allah saw some people gathered around a man, so he asked (what was happening) and they said: It is a man who is exhausted because of fasting. The Messenger of Allah said: It is not righteousness to fast when traveling.
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.
Muhammad bin 'Abdur-Rahman said: Someone who heard it from Jabir told me something similar.