(42) باب الصَّوْمِ فِي السَّفَرِ
Narrated Ibn 'Abbas:
The Prophet (ﷺ) left Medina for Mecca till he reached 'Usfan, He then called for a vessel (of water). It was raised to his mouth to show it to the people, and that was in Ramadan. Ibn 'Abbas used to say: The Prophet (ﷺ) fasted and he broke his fast. He who likes may fast and he who likes may break.
Reference: Sunan Abi Dawud 2404
In-book reference: Book 14, Hadith 92
English translation: Book 13, Hadith 2398