Reference: Fataawa Ramadhaan – Volume 1, Page 306, Fatwa No.249
al-Fataawa libni ‘Uthaymeen – Kitaab ad-Da’wah, Volume 1, Pages 179-180
Question: For which type of journey is not having to fast permissible?
Response: The journey for which it is permissible to shorten the prayer and not fast is approximately 83 kilometres. There are some amongst the scholars who do not specify a distance for the journey, rather, all that is commonly understood as a journey amongst the people constitutes a journey. The Messenger of Allaah (sal-Allaahu ‘alayhi wa-sallaam) used to shorten the prayer if he travelled 3 faraasikh (plural of farsakh, i.e. 3 miles – which is equal to 9 miles).
And for the impermissible journey, it is not acceptable to shorten the prayer or not to fast because a journey [undertaken] for [any] evil acts is not appropriate for [such a] permissibility. However, some of the people of knowledge do not differentiate between a journey [undertaken] for [any] evil acts or a journey in obedience [to Allaah] for the generality of the evidence [available].
And Allaah [alone] has the Complete knowledge [of all affairs].