Sahih Muslim 2675
صحيح مسلم#2675Sahihوَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا وَكِيعٌ، عَنِ ابْنِ عَوْنٍ، عَنْ زِيَادِ بْنِ جُبَيْرٍ، قَالَ جَاءَ رَجُلٌ إِلَى ابْنِ عُمَرَ - رضى الله عنهما - فَقَالَ إِنِّي نَذَرْتُ أَنْ أَصُومَ يَوْمًا فَوَافَقَ يَوْمَ أَضْحَى أَوْ فِطْرٍ . فَقَالَ ابْنُ عُمَرَ رضى الله عنهما أَمَرَ اللَّهُ تَعَالَى بِوَفَاءِ النَّذْرِ وَنَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم عَنْ صَوْمِ هَذَا الْيَوْمِ .
Ziyad b. Jubair reported that a person came to Ibn 'Umar (Allah be pleased with them) and said:I had taken a vow that I would fast on the day (but it accidentally) synchronises with the day of Adha or the day of Fitr. Thereupon Ibn 'Umar (Allah be pleased with him) said: Allah, the Exalted, has commanded fulfilling of the vow, but the Messenger of Allah (ﷺ) has forbidden the observance of fast on this day
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: 13:181