Qaza reported,

I came to Abu Saeed Khudri when many people were gathered around him. When the crowd dispersed, I said, "I am not going to ask you about what these people were asking you."I asked him about fasting while traveling.He said, "We traveled with the Messenger of Allah ﷺ toward Makkah while fasting. We stopped at a place, and the Messenger of Allah ﷺ said, 'You are drawing close to your enemy, and breaking the fast will give you more strength.' It was a concession, so some of us fasted and some of us broke the fast.Then we stopped at another place, and he said, 'You will meet your enemy in the morning, and breaking the fast will give you more strength, so break your fast.' This was a firm command, so we broke our fast."Then he said, "Later, you would see us fasting with the Messenger of Allah ﷺ while traveling."

عن قزعة، قال

أتيت أبا سعيد الخدري رضي الله عنه وهو مكثور عليه، فلما تفرق الناس عنه، قلت: إني لا أسألك عما يسألك هؤلاء عنه. سألته عن الصوم في السفر؟ فقال: سافرنا مع رسول الله ﷺ إلى مكة ونحن صيام. قال: فنزلنا منزلا، فقال رسول الله ﷺ: إنكم قد دنوتم من عدوكم والفطر أقوى لكم. فكانت رخصة فمنا من صام، ومنا من أفطر. ثم نزلنا منزلا آخر، فقال: إنكم مصبحوا عدوكم، والفطر أقوى لكم، فأفطروا. وكانت عزمة، فأفطرنا. ثم قال: رأيتنا نصوم مع رسول الله ﷺ بعد ذلك في السفر.