وَعَن حَمْزَة بن عَمْرو السّلمِيّ أَنَّهُ قَالَ: يَا رَسُولَ اللَّهِ إِنِّي أَجِدُ بِي قُوَّةً عَلَى الصِّيَامِ فِي السَّفَرِ فَهَلْ عَلَيَّ جُنَاحٌ؟ قَالَ: «هِيَ رُخْصَةٌ مِنَ اللَّهِ عَزَّ وَجَلَّ فَمَنْ أَخَذَ بِهَا فَحَسَنٌ وَمَنْ أَحَبَّ أَنْ يَصُومَ فَلَا جُنَاحَ عَلَيْهِ» . رَوَاهُ مُسلم

Hamza b. ‘Amr al-Aslami told God’s messenger that he found himself strong enough to fast while travelling and asked whether it would be wrong for him to do so. He was told that licence had been given by God who is great and glorious, so that if anyone acted upon this he did well, but if anyone wished to fast he would not be guilty of sin. Muslim transmitted it.