The Book of Fasting
22/53. Chapter:
Mentioning the saying: "The one who fasts while travelling is like the one who does not fast while a resident"
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ أَبَانَ الْبَلْخِيُّ، قَالَ حَدَّثَنَا مَعْنٌ، عَنِ ابْنِ أَبِي ذِئْبٍ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ، قَالَ يُقَالُ الصِّيَامُ فِي السَّفَرِ كَالإِفْطَارِ فِي الْحَضَرِ .
It was narrated that 'Abdur-Rahman bin 'Awf said: "It is said that fasting while traveling is like not fasting while a resident." (Daif)
Reference : Sunan an-Nasa'i 2284In-book reference : Book 22, Hadith 195English translation : Vol. 3, Book 22, Hadith 2286