Sahih Bukhari Volume 4, Book 52, Hadith Number 272.
Narated By Al-Bara : I saw Allah’s Apostle on the day (of the battle) of the Trench carrying earth till the hair of his chest were covered with dust and he was a hairy man. He was reciting the following verses of ‘Abdullah (bin Rawaha): “O Allah, were it not for You, We would not have been guided, Nor would we have given in charity, nor prayed. So, bestow on us calmness, and when we meet the enemy. Then make our feet firm, for indeed, Yet if they want to put us in affliction, (i.e. want to fight against us) we would not (flee but withstand them).” The Prophet used to raise his voice while reciting these verses. (See Hadith No. 432, Vol. 5).