Hadith 1121
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، - رضى الله عنها - أَنَّهَا قَالَتْ سَأَلَ حَمْزَةُ بْنُ عَمْرٍو الأَسْلَمِيُّ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنِ الصِّيَامِ فِي السَّفَرِ فَقَالَ " إِنْ شِئْتَ فَصُمْ وَإِنْ شِئْتَ فَأَفْطِرْ " .
'A'isha (Allah be pleased with her) reported that Hamza b. 'Amr al-Aslami asked the Messenger of Allah (ﷺ) about fasting on a journey, and he (the Holy Prophet) said:
Fast if you like and break it if you like.
Reference : Sahih Muslim 1121a
In-book reference : Book 13, Hadith 131
USC-MSA web (English) reference : Book 6, Hadith 2487