Sahih al-Bukhari 1994
صحيح البخاري#1994Sahihحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا مُعَاذٌ، أَخْبَرَنَا ابْنُ عَوْنٍ، عَنْ زِيَادِ بْنِ جُبَيْرٍ، قَالَ جَاءَ رَجُلٌ إِلَى ابْنِ عُمَرَ ـ رضى الله عنهما ـ فَقَالَ رَجُلٌ نَذَرَ أَنْ يَصُومَ يَوْمًا، قَالَ أَظُنُّهُ قَالَ الاِثْنَيْنِ، فَوَافَقَ يَوْمَ عِيدٍ. فَقَالَ ابْنُ عُمَرَ أَمَرَ اللَّهُ بِوَفَاءِ النَّذْرِ، وَنَهَى النَّبِيُّ صلى الله عليه وسلم عَنْ صَوْمِ هَذَا الْيَوْمِ.
Narrated Ziyad bin Jubair:A man went to Ibn `Umar and said, "A man vowed to fast one day (the sub-narrator thinks that he said that the day was Monday), and that day happened to be `Id day." Ibn `Umar said, "Allah orders vows to be fulfilled and the Prophet (ﷺ) forbade the fasting on this day (i.e. Id)
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 al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 30:100