Sahih al-Bukhari 2835
Sahih al-Bukhari · Book 56: Fighting for the Cause of Allah (Jihaad) · The digging of the Khandaq (trench)
Narrated Anas:
حَدَّثَنَا 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.
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 I 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."