"I used to fast continually at the time of the Messenger of Allah. I said: 'O continually while traveling.' He said: 'If you wish then fast, and if you wish then do not fast."' (Using translation from Nasāʾī 2300)
كُنْتُ أَسْرُدُ الصِّيَامَ عَلَى عَهْدِ رَسُولِ اللهِ ﷺ فَقُلْتُ يَا رَسُولَ اللهِ إِنِّي أَسْرُدُ الصِّيَامَ فِي السَّفَرِ؟ قَالَ «إِنْ شِئْتَ فَصُمْ وَإِنْ شِئْتَ فَأَفْطِرْ»