Sahih Muslim 2609
صحيح مسلم#2609Sahihوَحَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ عَبْدِ الْكَرِيمِ، عَنْ طَاوُسٍ، عَنِ ابْنِ، عَبَّاسٍ - رضى الله عنهما - قَالَ لاَ تَعِبْ عَلَى مَنْ صَامَ وَلاَ عَلَى مَنْ أَفْطَرَ قَدْ صَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي السَّفَرِ وَأَفْطَرَ .
Ibn Abbas (Allah be pleased with him) reported:Do not condemn one who observes fast, or one who does not observe (in a journey). for the Messenger of Allah (ﷺ) observed fast in a journey or he did not observe it (too)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 13:115