Sahih Bukhari, Chapter: Jihaad (Fighting for the cause of Allah)

On the day (of the battle) of Al-Ahzab (the confederates) I saw the Prophet (SAW) carrying earth, and the earth was covering the whiteness of his abdomen. And he was saying, "Without You (O Allah!) we would have got no guidance, nor given in charity, nor offered salat (prayers). So please bless us with tranquility and make firm our feet when we meet our enemies. Indeed (these) people have rebelled against us but never shall we yield if they try to bring Fitnah (affliction, trial) upon us."