Jabir bin Abdullah reported,

The Messenger of Allah ﷺ was on a journey when he saw a man around whom people had gathered, with shade being provided over him. He asked, "What is the matter with him?"They replied, "He is a man who is fasting."The Messenger of Allah ﷺ said, "It is not righteousness to fast while traveling."

Muslim 2612

Sahih

حدثنا أبو بكر بن أبي شيبة ومحمد بن المثنى وابن بشار جميعا عن محمد بن جعفر قال أبو بكر حدثنا غندر عن شعبة عن محمد بن عبد الرحمن بن سعد عن محمد بن عمرو بن الحسن

عن جابر بن عبد الله رضي الله عنهما قال

كان رسول الله ﷺ في سفر فرأى رجلا قد اجتمع الناس عليه وقد ظلل عليه فقال ما له قالوا رجل صائم فقال رسول الله ﷺ ليس من البر أن تصوموا في السفر

مسلم 2612صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Fasting
Chapter
Permissibility of fasting and breaking the fast in Ramadan for a traveler not in disobedience when his journey is two stages or more, and that it is better for one who can bear it without harm to fast and for one who finds it difficult to break the fast
Numbering
Darussalam 2612
Muslim 2612