أَخْبَرَنَا حُمَيْدُ بْنُ مَسْعَدَةَ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الْعَوَّامِ بْنِ حَوْشَبٍ، قَالَ قُلْتُ لِمُجَاهِدٍ الصَّوْمُ فِي السَّفَرِ قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَصُومُ وَيُفْطِرُ .
It was narrated that Al-'Awwam bin Hawshab said: "I said to Mujahid: 'What about fasting while traveling?' He said: 'The Messenger of Allah used to fast (sometimes) and not fast (sometimes)."' Translation Not Available
Book Ref: Sunan An Nisai Book 22 Hadith 2292
Web Ref: Sunan An Nisai Vol 3 Book 22 Hadith 2294