After World War I, Germany's economy was not doing well. There was also a lot of shame and anger over losing World War I as well. What Hitler and the Nazi party needed was a scapegoat of sorts. In order to help unify and inspire the downtrodden German people, the Nazis needed to lay the blame for all of their misery on someone or something.
Jewish people were a convenient target. They have historically been discriminated against by all kinds of people, sometimes for ethnic reasons, sometimes for religious reasons, and sometimes for economic reasons. If the Nazis were going to push an Aryan, Judeo Christian race, they needed to go after people that didn't fit. The Jews fit that bill. Most would not have blond hair and blue eyes and for sure were not Christian. In the eyes of the Nazi party, they were very un-German, and therefore needed to be removed. That's a part of the reason why the Jewish concentration camps and beatings were a part of the period.
Other groups of people suffered under the Nazi persecution as well. Gypsies, people with disabilities, Poles, people of African descent, homosexuals, and Jehovah's Witnesses were persecuted.
An extreme form of nationalism emerged in Germany after the first World War. Adolf Hitler and the Nazis believed that changes in society such as the growth of a more political working class was leading to instability and lack of unity in the German Society. In order to protect the 'volk' (people) it was necessary they stated to unite the people behind a common cause. The common cause being, the greatness of the German State. This could be achieved through expansion and a superior German pure race. 'Foreigners' were not tolerated this included the Jews.
The Jews were rising as a wealthy people and they were blamed by the Nazis as the ones who led Germany to lose in the war. Therefore, they were the targets. Many Jews, Gypsies, disabled persons or people seen as different were sent to concentration camps where they were killed. It must be noted that they were not only beaten but many starved to death and were placed in concentration camps. As these people were seen as unfit for 'a pure blooded German Society.'