Language:
كتاب الجهاد والسير
56  
Fighting for the Cause of Allah (Jihaad)
(34)
Chapter: The digging of the Khandaq (trench)
(34)
باب حَفْرِ الْخَنْدَقِ
Sahih al-Bukhari 2837

Narrated Al-Bara:

On the day (of the battle) of Al-Ahzab (i.e. clans) I saw the Prophet (ﷺ) carrying earth, and the earth was covering the whiteness of his `Abdomen. And he was saying, "Without You (O Allah!) we would have got no guidance, nor given in charity, nor prayed. So please bless us with tranquility and make firm our feet when we meet our enemies. Indeed (these) people have rebelled against (oppressed) us but never shall we yield if they try to bring affliction upon us."

حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ ـ رضى الله عنه ـ قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَوْمَ الأَحْزَابِ يَنْقُلُ التُّرَابَ وَقَدْ وَارَى التُّرَابُ بَيَاضَ بَطْنِهِ، وَهُوَ يَقُولُ لَوْلاَ أَنْتَ مَا اهْتَدَيْنَا وَلاَ تَصَدَّقْنَا وَلاَ صَلَّيْنَا‏.‏ فَأَنْزِلِ السَّكِينَةَ عَلَيْنَا وَثَبِّتِ الأَقْدَامَ إِنْ لاَقَيْنَا‏.‏ إِنَّ الأُلَى قَدْ بَغَوْا عَلَيْنَا إِذَا أَرَادُوا فِتْنَةً أَبَيْنَا‏.‏
Reference : Sahih al-Bukhari 2837
In-book reference : Book 56, Hadith 53
USC-MSA web (English) reference : Vol. 4, Book 52, Hadith 90
  (deprecated numbering scheme)