Sahih Bukhari Volume 4, Book 52, Hadith Number 140.

Narated By Anas : We were with the Prophet (on a journey) and the only shade one could have was the shade made by one’s own garment. Those who fasted did not do any work and those who did not fast served the camels and brought the water on them and treated the sick and (wounded). So, the Prophet said, “Today, those who were not fasting took (all) the reward.”