Sahih al-Bukhari 2835
صحيح البخاري#2835Sahihحَدَّثَنَا أَبُو مَعْمَرٍ، حَدَّثَنَا عَبْدُ الْوَارِثِ، حَدَّثَنَا عَبْدُ الْعَزِيزِ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ جَعَلَ الْمُهَاجِرُونَ وَالأَنْصَارُ يَحْفِرُونَ الْخَنْدَقَ حَوْلَ الْمَدِينَةِ، وَيَنْقُلُونَ التُّرَابَ عَلَى مُتُونِهِمْ وَيَقُولُونَ نَحْنُ الَّذِينَ بَايَعُوا مُحَمَّدًا عَلَى الإِسْلاَمِ مَا بَقِينَا أَبَدًا وَالنَّبِيُّ صلى الله عليه وسلم يُجِيبُهُمْ وَيَقُولُ اللَّهُمَّ إِنَّهُ لاَ خَيْرَ إِلاَّ خَيْرُ الآخِرَهْ فَبَارِكْ فِي الأَنْصَارِ وَالْمُهَاجِرَهْ.
Narrated Anas:The Emigrants and the Ansar started digging the trench around Medina carrying the earth on their backs and saying, "We are those who have given a pledge of allegiance to Muhammad that we will carry on Jihad as long as we live." The Prophet (ﷺ) kept on replying, "O Allah, there is no good except the good of the Hereafter; so confer Your Blessings on the Ansar and the Emigrants
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: 56:51