Sahih al-Bukhari 6618
صحيح البخاري#6618Sahihحَدَّثَنَا عَلِيُّ بْنُ حَفْصٍ، وَبِشْرُ بْنُ مُحَمَّدٍ، قَالاَ أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ سَالِمٍ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم لاِبْنِ صَيَّادٍ " خَبَأْتُ لَكَ خَبِيئًا ". قَالَ الدُّخُّ. قَالَ " اخْسَأْ فَلَنْ تَعْدُوَ قَدْرَكَ ". قَالَ عُمَرُ ائْذَنْ لِي فَأَضْرِبَ عُنُقَهُ. قَالَ " دَعْهُ، إِنْ يَكُنْ هُوَ فَلاَ تُطِيقُهُ، وَإِنْ لَمْ يَكُنْ هُوَ فَلاَ خَيْرَ لَكَ فِي قَتْلِهِ ".
Narrated Ibn `Umar:The Prophet (ﷺ) said to Ibn Saiyad, "I have kept for you a secret." Ibn Saiyad said, "Ad-Dukh." The Prophet said, "Keep quiet, for you cannot go beyond your limits (or you cannot exceed what has been foreordained for you)." On that, `Umar said (to the Prophet (ﷺ) ), "Allow me to chop off his neck!" The Prophet said, "Leave him, for if he is he (i.e., Ad-Dajjal), then you will not be able to overcome him, and if he is not, then you gain no good by killing 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: 82:24