Muwatta Malik 654

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ حُمَيْدٍ الطَّوِيلِ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّهُ قَالَ سَافَرْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي رَمَضَانَ فَلَمْ يَعِبِ الصَّائِمُ عَلَى الْمُفْطِرِ وَلاَ الْمُفْطِرُ عَلَى الصَّائِمِ ‏.‏

Yahya related to me from Malik from Humayd at-Tawil that Anas ibn Malik said, "We once travelled with the Messenger of Allah, may Allah bless him and grant him peace, in Ramadan, and those who were fasting did not find fault with those who were not, and those who were not fasting did not find fault with those who were

Reference

Muwatta Malik 654

In-book

Book 18, Hadith 25