Sahih Muslim Book - 13, Hadith - 2625

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ حَدَّثَنَا لَيْثٌ عَنْ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ عَنْ عَائِشَةَ - رضى الله عنها - أَنَّهَا قَالَتْ سَأَلَ حَمْزَةُ بْنُ عَمْرٍو الأَسْلَمِىُّ رَسُولَ اللَّهِ -صلى الله عليه وسلم- عَنِ الصِّيَامِ فِى السَّفَرِ فَقَالَ « إِنْ شِئْتَ فَصُمْ وَإِنْ شِئْتَ فَأَفْطِرْ ».

It was narrated that Rabiah said: “Qaza’ah narrated to me: ‘I came to Abu Sa’eed Al-khudri [may Allah be pleased with them] while he was surrounded by people. When the people dispersed from around him, I said: “I am not going to ask youi about what these people were asking. And I asked him about fasting while travelling.” He said: “We travelled with the Messenger of Allah to Makkah when we were fasting. We made a stop and the Messenger of Allah said: ‘You have drawn near to your enemy and breaking the fast will make you stronger.’ This was a concession, so some of us fasted and some did not. Then we made another stop and he said: ‘In the morning you are going to meet your enemy. And breaking the fast will make you stronger, so break the fast. ’ He emphasized it (the second time), so we broke the fast.” Then he said: “I remember we fasted with the Messenger of Allah after that, when travelling.”