Sahih al-Bukhari 1978
صحيح البخاري#1978Sahihحَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا غُنْدَرٌ، حَدَّثَنَا شُعْبَةُ، عَنْ مُغِيرَةَ، قَالَ سَمِعْتُ مُجَاهِدًا، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو ـ رضى الله عنهما ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " صُمْ مِنَ الشَّهْرِ ثَلاَثَةَ أَيَّامٍ ". قَالَ أُطِيقُ أَكْثَرَ مِنْ ذَلِكَ. فَمَا زَالَ حَتَّى قَالَ " صُمْ يَوْمًا وَأَفْطِرْ يَوْمًا " فَقَالَ " اقْرَإِ الْقُرْآنَ فِي شَهْرٍ ". قَالَ إِنِّي أُطِيقُ أَكْثَرَ. فَمَا زَالَ حَتَّى قَالَ فِي ثَلاَثٍ.
Narrated Mujahid from `Abdullah bin `Amr:The Prophet (ﷺ) said (to `Abdullah), "Fast three days a month." `Abdullah said, (to the Prophet) "I am able to fast more than that." They kept on arguing on this matter till the Prophet (ﷺ) said, "Fast on alternate days, and recite the whole Qur'an once a month." `Abdullah said, "I can recite more (in a month)," and the argument went on till the Prophet (ﷺ) said, "Recite the Qur'an once each three days." (i.e. you must not recite the whole Qur'an in less than three days)
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: 30:85