(15) باب جواز الصوم والفطر في شهر رمضان للمسافر في غير معصية إذا كان سفره مرحلتين فأكثر وأن الأفضل لمن أطاقه بلا ضرر أن يصوم ولمن يشق عليه أن يفطر
Ibn 'Abbas (Allah be pleased with him) reported that the Messenger of Allah (ﷺ) journeyed during the month of Ramadan in a state of fasting till he reached 'Usfan. He then ordered a cup containing drinking water and he drank that openly so that the people might see it, and broke the fast (and did not resume it) till he reached Mecca. Ibn 'Abbas (Allah be pleased with him) said:
Allah's Messenger (ﷺ) fasted and broke the fast, so he who wished fasted and he who wished to break it broke it.
Reference: Sahih Muslim 1113 e
In-book reference: Book 13, Hadith 114
USC-MSA web (English) reference(deprecated numbering scheme): Book 6, Hadith 2470