Sahih Muslim Book 19, Hadith Number 4442.

Chapter : The battle of Ahzab or Khandaq (the tribes or the ditch).

It has been reported on the authority of Barra’ who said: The Messenger of Allah (may peace be upon him) was carrying the earth with us on the Day of Ahzab and the whiteness of his belly had been covered with earth, (While engaged in this toil) he was reciting:

By God, if Thou hadst not guided us, we would have neither been guided aright nor practised charity, nor offered prayers. Descend on us peace and tranquillity. Behold I these people (the Meccans) refused to follow us. According to another version, he recited:

The chieftains (of the tribes) refused to follow us when they contemplated mischief, we rejected it. And with this (verse) he would raise his voice.