Sahih al-Bukhari 1736
صحيح البخاري#1736Sahihحَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عِيسَى بْنِ طَلْحَةَ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم وَقَفَ فِي حَجَّةِ الْوَدَاعِ، فَجَعَلُوا يَسْأَلُونَهُ، فَقَالَ رَجُلٌ لَمْ أَشْعُرْ فَحَلَقْتُ قَبْلَ أَنْ أَذْبَحَ. قَالَ " اذْبَحْ وَلاَ حَرَجَ ". فَجَاءَ آخَرُ فَقَالَ لَمْ أَشْعُرْ فَنَحَرْتُ قَبْلَ أَنْ أَرْمِيَ. قَالَ " ارْمِ وَلاَ حَرَجَ ". فَمَا سُئِلَ يَوْمَئِذٍ عَنْ شَىْءٍ قُدِّمَ وَلاَ أُخِّرَ إِلاَّ قَالَ افْعَلْ وَلاَ حَرَجَ.
Narrated `Abdullah bin `Amr:Allah's Messenger (ﷺ) stopped (for a while near the Jimar at Mina) during his last Hajj and the people started asking him questions. A man said, "Ignorantly I got my head shaved before slaughtering." The Prophet replied, "Slaughter (now) and there is no harm in it." Another man said, "Unknowingly I slaughtered the Hadi before doing the Rami." The Prophet (ﷺ) said, "Do Rami now and there is no harm in it." So, on that day, when the Prophet (ﷺ) was asked about anything (about the ceremonies of Hajj) done before or after (its stated time) his reply was, "Do it (now) and there is no harm
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: 25:214