Sahih Bukhari Volume 009, Book 090, Hadith Number 342.
Narrated By Al-Bara' bin 'Azib : The Prophet was carrying earth with us on the day of the battle of Al-Ahzab (confederates) and I saw that the dust was covering the whiteness of his abdomen, and he (the Prophet) was saying, "(O Allah) ! Without You, we would not have been guided, nor would we have given in charity, nor would we have prayed. So (O Allah!) please send tranquility (Sakina) upon us as they, (the chiefs of the enemy tribes) have rebelled against us. And if they intend affliction (i.e. want to frighten us and fight against us) then we would not (flee but withstand them). And the Prophet used to raise his voice with it. (See Hadith No. 430 and 432, Vol. 5)