"Look! These are your brothers."
Maria says this to the schoolchildren when she brings them to the garden in the Club of the Sons, nestled high in the clouds. This statement reflects her idealism and her desire to teach the children of whom she is in charge that they ought to think of themselves as equal to the people who live in the upper levels, even if they are told they are inferior. Her statement proves inspiring not only to her charges, but to the impressionable and pure-hearted Freder.
"To my father."
Freder has just seen workers dying as they attempt to keep the city operating in the depths of the earth. He knows that the only way that anything will ever change is if his father is willing to help the workers and improve their lives, so he asks his driver to bring him directly to his father's office.
"Why was my son allowed to go into the machine rooms?"
Fredersen yells at his employee after Freder tells him he saw the horrible conditions in the workers' city. Fredersen does not want Freder getting mixed up in these kinds of class critiques and so scolds his assistants for not keeping a tighter watch on him.
Joh Fredersen: I must know! Where is my son?!!! The Thin Man: Tomorrow, thousands will ask in fury and desperation: Joh Fredersen, where is my son!
Towards the end of the film, after the workers have revolted and chaos has broken out in the city, Fredersen is worried about Freder's whereabouts and wonders where his son has gone. In an uncharacteristically critical way, the Thin Man suggests that many children from the workers' city have had their lives endangered by the violent revolution breaking out.
Joh Fredersen: Off where they belong... Freder: Of where they belong?...In the depths?...And if those in the depths one day rise against you?
After seeing the poor conditions in the workers' city, Freder goes to his father and tries to understand why conditions cannot be improved. Fredersen maintains that everyone is in their rightful place in society, but Freder fights back against this idea, suggesting that if Fredersen does not address the inequity soon, his workers will revolt and rise up.
"The mediator of the head and the hands must be the heart."
We first encounter this line at the start of the film as a kind of epigraph, a slogan through which to view the narrative. As a line of dialogue, it can be attributed to Maria, who preaches to the workers that the only way for them to communicate and cooperate with the upper classes and the powers that be is if someone steps in as a mediator between the two. The head is the symbol for the upper classes, the logicians of society, while the hands are a symbol for the workers, the people who carry out the work that keeps society running. The heart is the symbolic organ that can connect these two entities.
"'We shall build a tower that will reach to the stars!' Having conceived Babel, yet unable to build it themselves, they had thousands to build it for them. But those who toiled knew nothing of the dreams of those who planned. And the minds that planned the Tower of Babel cared nothing for the workers who built it."
Maria says this while addressing the group of workers in the catacombs of the workers' city. She uses the biblical story of the construction of the Tower of Babel as a stand-in for their own plights as workers. The parallels are clear: in order to build a huge tower that reached the heavens, the powerful members of society exploited the working class as slaves, without caring about their well-being.
"Death to the machines!"
This is the robotic version of Maria's rallying cry to the workers. She proposes a violent overthrow of the system, including destroying the machines that they are employed to work at. This is a highly self-destructive rallying cry, as the machines are what keep the city running and to destroy them all will only create chaos and death.
"Oh mediator, have you finally come?"
Upon seeing Freder for the first time, when he reveals himself during the meeting, Maria instantly recognizes him as the man who can save them all and serve as a mediator between the working and upper classes.
"Who told you to attack the machines, you fools? Without them you'll all die!"
The operator of the Heart Machine is disheartened to see all of his workers rising up and seeking to destroy the very machines which sustain life in their society. He pleads with them, asking them why they want to wreak havoc on the city and hurt themselves in the process.
