Musnad Abu Ya'la al-Mawsili 147:22

Abu Bakr ibn Abi Shaybah narrated to us, Abu Mu'awiyah narrated to us, from 'Asim, from Muwarriq, from Anas, who said: We were with the Messenger of Allah (peace be upon him) on a journey. Among us were those who were fasting, and among us were those who were not fasting. We descended at a stopping place on a hot day. Most of us were shaded by the people of the cloaks (those who had cloaks), and among us were those who were shielding themselves from the sun with their hands. He said: So the fasting ones fell (due to exhaustion), and the non-fasting ones stood up. They pitched the tents and gave water to the riding beasts. Then the Messenger of Allah (peace be upon him) said: "The non-fasting ones have taken the reward today."