Sahih Muslim 1803 a
The Book of Jihad and Expeditions
The Battle of Al-Ahzab (The Confederates), also known as Al-Khandaq (The Ditch)
It has been reported on the authority of Barra' who said: The Messenger of Allah (ﷺ) 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 You 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.