Hitler was very large on the idea of nationalism and Social Darwinism. He considered those with the most German blood to be the most pure and claimed anyone with mixed blood was polluted. Utilizing this, Jews were placed at the bottom of the hierarchy and actively discriminated against. Hitler used these ideas to blame the Jews for the downfall of the economy and labeled them as "enemies of the state".
After Hitler became Chancellor he immediately began passing anti-Jew laws. At first he simply wanted the Jews to leave German land, but the Jew didn't want to just give up their homes and land. This caused Hitler to change his policies to violence against Jews instead. This lead to Kristallnacht, or "The Night of Broken Glass," where Nazi supporters started destroying Jewish belongings such as shops, homes, and synagogues.
a burning synagogue during Kristallnacht (The Night of Broken Glass) - claimscon