Sahih al-Bukhari 6922
صحيح البخاري#6922Sahihحَدَّثَنَا أَبُو النُّعْمَانِ، مُحَمَّدُ بْنُ الْفَضْلِ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ أَيُّوبَ، عَنْ عِكْرِمَةَ، قَالَ أُتِيَ عَلِيٌّ ـ رضى الله عنه ـ بِزَنَادِقَةٍ فَأَحْرَقَهُمْ فَبَلَغَ ذَلِكَ ابْنَ عَبَّاسٍ فَقَالَ لَوْ كُنْتُ أَنَا لَمْ أُحْرِقْهُمْ لِنَهْىِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَلَقَتَلْتُهُمْ لِقَوْلِ رَسُولِ اللَّهِ صلى الله عليه وسلم " مَنْ بَدَّلَ دِينَهُ فَاقْتُلُوهُ ".
Narrated `Ikrima:Some Zanadiqa (atheists) were brought to `Ali and he burnt them. The news of this event, reached Ibn `Abbas who said, "If I had been in his place, I would not have burnt them, as Allah's Messenger (ﷺ) forbade it, saying, 'Do not punish anybody with Allah's punishment (fire).' I would have killed them according to the statement of Allah's Messenger (ﷺ), 'Whoever changed his Islamic religion, then kill him
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: 88:5