Sahih al-Bukhari 1947
Sahih al-Bukhari · Book 30: Fasting · Not to criticize each other for observing Saum or not (on journeys)
Narrated Anas bin Malik:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ ، عَنْ مَالِكٍ ، عَنْ حُمَيْدٍ الطَّوِيلِ ، عَنْ أَنَسِ بْنِ مَالِكٍ ، قَالَ كُنَّا نُسَافِرُ مَعَ النَّبِيِّ صلى الله عليه وسلم فَلَمْ يَعِبِ الصَّائِمُ عَلَى الْمُفْطِرِ، وَلاَ الْمُفْطِرُ عَلَى الصَّائِمِ.
We used to travel with the Prophet (ﷺ) and neither did the fasting persons criticize those who were not fasting, nor did those who were not fasting criticize the fasting ones.