Ibn Majah

Benefit:
From this it is understood that if a person is able to endure, he may also fast while traveling,
even if there is hardship in it.

Hadith Commentary:
It is understood from this that if a traveler, at the beginning of his journey during Ramadan, keeps a fast, and later on experiences hardship, then he may, without hesitation, break his fast.

Hadith Commentary:
(1)
From this hadith, it is also established that both fasting and not fasting during travel are permissible, because the narration in Sahih Muslim indicates that the mentioned journey took place during the month of Ramadan. The words of the hadith are: We set out with the Messenger of Allah (sallallahu alayhi wa sallam) for a journey during the month of Ramadan in intense heat. (Sahih Muslim, Kitab al-Siyam, Hadith: 2630(1122))

(2)
It should be clear that the mentioned journey was other than the Battle of Badr and the Conquest of Makkah, because Abdullah bin Rawahah (radi Allahu anhu) was martyred in the Battle of Mu'tah, and the Conquest of Makkah occurred after that. And it could not have been the Battle of Badr, because the narrator of the hadith, Abu Darda (radi Allahu anhu), had not yet embraced Islam at that time.

(3)
From this hadith, it is understood that if a person has the strength to fast during travel and does not experience any hardship, then there is no harm in fasting. (Fath al-Bari: 4/233)

(4)
This hadith also shows that if a person begins a journey while fasting in Ramadan, and later experiences difficulty, he may break his fast without hesitation; there is no harm in this.