What is the meaning of what Ben Ross wrote on the board?

Mr. Ross’ is mirroring some Nazi behaviors. The short slogan—“STRENGTH THROUGH DISCPLINE”–– simplifes a complex set of ideas and behaviors. The Nazis also relied heavily on slogans and symbols like the swastika and the eagle. Furthermore, they enthusiastically embraced personal discipline; their ideology was not just political but also extended deep into an individual’s daily life.