I was on a journey when I came to the Prophet ﷺ while I was fasting and he was eating.He said, "Come, eat."I replied, "I am fasting."He said, "Come here. Do you not know what Allah has waived for the traveler?"I asked, "And what has He waived for the traveler?"He answered, "Fasting and half of the prayer."
أخبرنا قتيبة قال حدثنا أبو عوانة عن أبي بشر عن هانئ بن الشخير
كنت مسافرا فأتيت النبي ﷺ وأنا صائم وهو يأكل قال هلم قلت إني صائم قال تعال ألم تعلم ما وضع الله عن المسافر قلت وما وضع عن المسافر قال الصوم ونصف الصلاة
[Sahih], and it is in Kubra, hadith no. 2588, and the hadith has many corroborating narrations.