Holy Fool
performed by The Boondock Saints

The film centers around Catholic Irish American fraternal twins, Connor and Murphy MacManus, who become vigilantes after killing two members of the Russian Mafia in self-defense. After a message from God, the brothers, together with their friend David Della Rocco, set out to rid their home city of Boston, Massachusetts of crime and evil; all the while being pursued by FBI agent Paul Smecker.