Morality and Ethics
The movie begins with a priest giving a homily about the harm that is caused when good people choose not to get involved and fight evil where they find it. Symbolically the McManus brothers arise from their seats, walk up to the alter, and kiss the feet of the statue of Jesus Christ. They have heard the message. Later in a shared dream, the brothers a spoken to by God. The message: to use violence to fight evil is "righteous violence". The brothers act with a moral authority to be judge, jury, and executioner. The ethics of this is murky. Troy Duffy, the movie's director, touches on this at the end the film where a series of television interviews with Boston residents are shown. They display a diversity of viewpoints. Despite this, the main body of the movie seems to have a less balanced view. The brothers actions or punishments are presented as acts of retribution. The legitimization of their actions are enhanced by reference to religious symbols and rituals.
In this video, the brothers describe to their friend how they define what is evil, and therefore what they are justified in destroying. This is a description of their ethical code.