The Germans wrecked havoc on Europe during WWi. However they lost that war and as a result were forced to sign treaties and pacts of all kind. The Europeans, especially their leaders enforced all sorts of sanction on the German people, which led to a devastating German depression. They were treated like dirt, had no jobs, little food and no pride. This went on for several years, which really took its toll on the German people. Along comes Hitler, making his speeches and inciting the German people. he was actually arrested and put in prison for trying to over throw the then German government. It was in prison that he wrote "Mein Kampt", or my struggles. When he was released, Germany had attained a more respectable attitude from European nations. He took advantage of that and again started with the speeches and formed the Nazi party, A small following, became a large following, which became a huge following. The German people were desperate for a good life again and Hitler promised them that if they followed him, he would give it back to them. They still had elections in Germany at that time and he ran for Chancellor. He won thumbs down and he started following through on his promises. The Germans became self sufficient, jobs became available in huge quantities and Germans started to get their lives back, including German Jews, who were punished the same along side their Christian German friends and neighbors.
But Hitler needed a scape goat as to why things had gotten so bad for the Germans and because of his irrational hatred of the Jews, he had his scape goat. The Jews did this to you. They owned all the banks, all big business and continued to have the good life while the rest of the Germans suffered. Most Germans, at least in the beginning believed him and thus started the persecution of the Jews.