We were traveling with the Messenger of Allah ﷺ. Some of us were fasting and some were not. We stopped to rest on a hot day and took shelter in whatever shade we could find. Those who were fasting collapsed from exhaustion, while those who had broken their fast got up and watered the mounts.The Messenger of Allah ﷺ said, "Those who broke their fast have taken the reward today."
أخبرنا إسحق بن إبراهيم قال حدثنا أبو معاوية قال حدثنا عاصم الأحول عن مورق العجلي
كنا مع رسول الله ﷺ في السفر فمنا الصائم ومنا المفطر فنزلنا في يوم حار واتخذنا ظلالا فسقط الصوام وقام المفطرون فسقوا الركاب فقال رسول الله ﷺ ذهب المفطرون اليوم بالأجر
Muslim narrated it in the Book of Fasting, the chapter on the reward of one who breaks the fast while traveling if he undertakes the work, hadith no. 1119, from the hadith of Abu Muawiya al-Darir. Bukhari narrated it in the Book of Jihad, the chapter on the merit of service in a military expedition, hadith no. 2890, from the hadith of Asim al-Ahwal, through the same chain. It is also found in al-Kubra, hadith no. 2592.