Hadith: It is not from righteousness to fast while traveling

عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ رَضِيَ اللَّهُ عَنْهُما قَالَ:
كَانَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ فِي سَفَرٍ، فَرَأَى زِحَامًا وَرَجُلًا قَدْ ظُلِّلَ عَلَيْهِ، فَقَالَ: «مَا هَذَا؟»، فَقَالُوا: صَائِمٌ، فَقَالَ: «لَيْسَ مِنَ البِرِّ الصَّوْمُ فِي السَّفَرِ»، وَفِي لَفْظٍ لِمُسلِمٍ: «عَلَيْكُمْ بِرُخْصَةِ اللهِ الَّذِي رَخَّصَ لَكُمْ».
[صحيح] - [متفق عليه] - [صحيح البخاري: 1946]

Jābir ibn ‘Abdullah (may Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) was on a journey and saw a crowd of people, and a man was being shaded (by them). He asked: "What is the matter with that (man)?" They said: He is fasting. Thereupon, he said: "It is not from righteousness to fast while traveling." In another version by Muslim, he said: "Take advantage of the concession that Allah has granted you."
[Authentic hadith] - [Narrated by Bukhari & Muslim] - [Sahih Bukhari - 1946]

Explanation

The Messenger of Allah (ﷺ) was on a journey and saw a man over whom people had gathered, shading him from the heat of the sun and his intense thirst. The Prophet (ﷺ) asked: What is the matter with him? They said: He is fasting. He said: It is not an act of righteousness to fast while traveling. You should accept Allah's concession that He has granted you.

Benefits from the Hadith

1. Highlighting the ease of the Islamic Shariah.
2. It is permissible to fast while traveling, and it is also permissible to take the concession by breaking the fast.
3. Fasting while traveling is disliked if it causes hardship, unless it reaches the point of endangering one's life, in which case it becomes forbidden.
4. An-Nawawi said: It is not from righteousness to fast while traveling—meaning: when it causes hardship or harm. The context of the Hadīth indicates this interpretation.
5. The Prophet's care and concern for his Companions, and his inquiry about their conditions.