What are important quotes in The Boy in the Striped Pajamas that are related to power?

Power
is a fairly broad prompt. It could relate to any number of themes present in the book.
Characters can be powerful due to their usage of violence against another person or group. Power
can be shown in perseverance through suffering, and it can even be seen in how the family unit
can be a powerful structure of hope.

One such character that exerts physical
and psychological power over other people in the book is Lieutenant Kotler. He is an easily
angered man, and he uses fear to maintain power over people:

Lieutenant Kotler grew very angry with Pavel and no one-not Bruno, not Gretel, not
Mother and not even Father-stepped in to stop him doing what he did next, even though none of
them could watch.

Another good example of Kotler
maintaining his position of power comes when he callously shoots a dog for nothing more than
barking:

he saw a dog approach the fence and start barking
loudly, and when Lieutenant Kotler heard it he marched right over to the dog and shot
it.

On a brighter note, the book also explores the power
of friendship. Bruno and Shmuel develop a strong bond. That bond allows them to empathize with
each other as well as just enjoy each other's company. We also see how that bond is powerful
enough to make Bruno feel guilt and shame when he does something to ruin the
friendship:

I can't believe I didn't tell him the truth.
I've never let a friend down like that before. Shmuel, I'm ashamed of myself.