وَحَدَّثَنَا أَبُو الرَّبِيعِ الزَّهْرَانِيُّ، حَدَّثَنَا حَمَّادٌ، - وَهُوَ ابْنُ زَيْدٍ - حَدَّثَنَا هِشَامٌ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، - رضى الله عنها - أَنَّ حَمْزَةَ بْنَ عَمْرٍو الأَسْلَمِيَّ، سَأَلَ رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي رَجُلٌ أَسْرُدُ الصَّوْمَ ‏.‏ أَفَأَصُومُ فِي السَّفَرِ قَالَ ‏"‏ صُمْ إِنْ شِئْتَ وَأَفْطِرْ إِنْ شِئْتَ ‏"‏ ‏.‏

'A'isha (Allah be pleased with her) reported that Hamza b. Amr al-Aslami asked the Messenger of Allah (PBUH) thus: Messenger of Allah, I am a person devoted much to fasting. Should I fast during the journey? He (the Holy Prophet) said: Fast if you like and break it if you like. Translation Not Available

Book Ref: Sahih Muslim Book 13 Hadith 2488
Web Ref:  Sahih Muslim Book 6 Hadith 1121 b