Sunan an-Nasa'i 2280
It was narrated from Hani bin 'Abdullah bin Ash-Shikhkhir from Balharish,  from a man from Balharish, that his father said:
"we had been travelijng for as long as Allah willed, then we came to the Messenger of Allah and he was eating. He said: 'Come and eat.' I said: 'I am fasting.' The Messenger of Allah said: 'I will tell you about fasting. Allah has waived fasting and half of the prayer for the traveler."'
أَخْبَرَنَا عَبْدُ الرَّحْمَنِ بْنُ مُحَمَّدِ بْنِ سَلاَّمٍ، قَالَ حَدَّثَنَا أَبُو دَاوُدَ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ أَبِي بِشْرٍ، عَنْ هَانِئِ بْنِ عَبْدِ اللَّهِ بْنِ الشِّخِّيرِ، عَنْ رَجُلٍ، مِنْ بَلْحَرِيشٍ عَنْ أَبِيهِ، قَالَ كُنَّا نُسَافِرُ مَا شَاءَ اللَّهُ فَأَتَيْنَا رَسُولَ اللَّهِ صلى الله عليه وسلم وَهُوَ يَطْعَمُ فَقَالَ ‏"‏ هَلُمَّ فَاطْعَمْ ‏"‏ ‏.‏ فَقُلْتُ إِنِّي صَائِمٌ ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أُحَدِّثُكُمْ عَنِ الصِّيَامِ إِنَّ اللَّهَ وَضَعَ عَنِ الْمُسَافِرِ الصَّوْمَ وَشَطْرَ الصَّلاَةِ ‏"‏ ‏.‏