Sahih Bukhari Volume 5, Book 64, Hadith 4106

حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ ـ رضى الله عنه ـ قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم يَنْقُلُ التُّرَابَ يَوْمَ الْخَنْدَقِ حَتَّى أَغْمَرَ بَطْنَهُ أَوِ اغْبَرَّ بَطْنُهُ يَقُولُ وَاللَّهِ لَوْلاَ اللَّهُ مَا اهْتَدَيْنَا وَلاَ تَصَدَّقْنَا وَلاَ صَلَّيْنَا فَأَنْزِلَنْ سَكِينَةً عَلَيْنَا وَثَبِّتِ الأَقْدَامَ إِنْ لاَقَيْنَا إِنَّ الأُلَى قَدْ بَغَوْا عَلَيْنَا إِذَا أَرَادُوا فِتْنَةً أَبَيْنَا وَرَفَعَ بِهَا صَوْتَهُ أَبَيْنَا أَبَيْنَا‏

Narrated By Al-Bara : The Prophet was carrying earth on the day of Al-Khandaq till his abdomen was fully covered with dust, and he was saying, "By Allah, without Allah we would not have been guided, neither would we have given in charity, nor would we have prayed. So (O Allah), please send Sakina (i.e. calmness) upon us, and make our feet firm if we meet the enemy as the enemy have rebelled against us, and if they intended affliction, (i.e. want to frighten us and fight against us then we would not flee but withstand them)." The Prophet used to raise his voice saying, "Abaina! Abaina! (i.e. would not, we would not)."