Sahih al-Bukhari, Book 30, Hadith 53 (In-Book) ⓘ

Narrated Jabir bin `Abdullah: Allah's Messenger was on a journey and saw a crowd of people, and a man was being shaded (by them). He asked, "What is the matter?" They said, "He (the man) is fasting." The Prophet said, "It is not righteousness that you fast on a journey."

حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الرَّحْمَنِ الأَنْصَارِيُّ، قَالَ سَمِعْتُ مُحَمَّدَ بْنَ عَمْرِو بْنِ الْحَسَنِ بْنِ عَلِيٍّ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ ـ رضى الله عنهم ـ قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي سَفَرٍ، فَرَأَى زِحَامًا، وَرَجُلاً قَدْ ظُلِّلَ عَلَيْهِ، فَقَالَ ‏"‏ مَا هَذَا ‏"‏‏.‏ فَقَالُوا صَائِمٌ‏.‏ فَقَالَ ‏"‏ لَيْسَ مِنَ الْبِرِّ الصَّوْمُ فِي السَّفَرِ ‏"‏‏.‏