The Republic
What is the connection Thrasymachus makes between justice, injustice, and happiness?
thrasmychus definition
thrasmychus definition
There is too much information for me to share it all here. Check out the link below, I think it will help you formulate your answer. If you have any more specific questions, feel free to come back and ask them here.
http://aporia.byu.edu/pdfs/buenting-revisiting_thrasymachus_challenge.pdf