Hameed bin Hilal حميد بن هلال · The Book on Jihad

"During the year of the conquest, when the Prophet (ﷺ) reached Marr Zahran, he told us that we would meet the enemy. So he ordered us to break the fast, and we broke our fast." This Hadith is Hasan Sahih, and there is something on this topic from Ibn 'Umar.