It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him), he says: We used to go on expeditions with the Messenger of Allah (peace and blessings be upon him), some of us would fast and some would not. The fasting ones would not show displeasure towards those who did not fast, and those who did not fast would not show displeasure towards those who fasted. Their view was that whoever had the strength to fast while traveling and he fasted, then that was good for him, and whoever felt weakness and did not fast, then that was good for him.