Ubaidullah bin 'Umar bin Hafs عبيد الله بن عمر بن حفص بن عاصم · Fasting (Kitab Al-Siyam)

The Messenger of Allah (ﷺ) as saying: If anyone is on a journey and Ramadan comes... He then narrated the rest of the tradition to the same effect.

Mansur al-Kalbi said: Dihyah ibn Khalifah once went out from a village of Damascus at as much distance as it measures between Aqabah and al-Fustat during Ramadan; and that is three miles. He then broke his fast and the people broke their fast along with him. But some of them disliked to break their fast. When he came back to his village, he said: I swear by Allah, today I witnessed a thing of which I could not even think…

The Quraish used to fast on the day of 'Ashurah in pre Islamic days. The Messenger of Allah (ﷺ) would fast on it in pre-Islamic period. When the Messenger of Allah (ﷺ) came to Medina, he fasted on it and commanded to fast on it. When the fast of Ramadan was prescribed, that became obligatory, and (fasting on) 'Ashurah was abandoned. He who wishes may fast on it and he who wishes may leave it.