Realizing that the majority of merchants were Jewish, Hitler blamed the Jews for the fall of the economy and its runaway inflation in the 1930s in Germany. Along with the merchants, Jewish doctors and lawyers also controlled much of the money. Because of this terrible condition of the economy, Hitler was able to incite the German people to rally against them. Afterall, Hitler reasoned, the Jews were invaders, not true citizens of Germany; they were not Aryan. In addition, Hitler considered them inferior; their presence, their appearance, their history was repugnant to him. In short, the Jews were the perfect scapegoat for the German people' ills, especially since the Treaty of Versailles left Germany broke from paying reparations. The government wound up printing money causing inflation to rise drastically.The treaty of Versailles has been said to have been a Jewish conspiracy.
There are no 'concrete facts' for why Hitler hated Jews. He was a racist. He hated them for false reasons.
1) From the science of Eugenics (which is now proved wrong) He believed The Germans were 'The Super Race' and Germany was the 'Fatherland'. It was no place for inferior races like The Jews.
2) Approximately 1 in 4 Germans were Jewish, which made Christian Germans feel very uncomfortable. The Jews presented a good unifying focus for German unrest. Many people blame someone else for their own problems, politicians know this and use this.
3) It was a common belief that Jews were in conspiracy. There was a widely published 'secret Jewish handbook' called, "The Protocols of The Elders of Zion" which told the reader how to run The Jewish Conspiracy. It was supposedly a captured, top-secret Jewish text. In fact it was written by The Russian Secret Service as anti-Jewish propaganda. Even today you occasionally find extremists who claim "The Protocols of The Elders of Zion" is a geniune Jewish guide to global domination.
4) He genuinely believed Germans were the Master Race. The Jews were little more than animals. A pest like a rat that needed destroying.
5) The Jews have always been persecuted by Christians. They were blamed for killing Jesus. (who, ironically, was a Jew).
6) Martin Luther (a German that Hitler admired) wrote several books on the need to destroy or remove the Jews from Germany. We know Hitler read these works.
This question would takes books to provide a solid answer. A good place to start is World War I and the Versailles Treaty. Reparations were horrendous, but worse than reparations, Germany was deemed solely responsible for the War (not completely legitimate) and all Germans were to share the "war guilt." Additionally, parts of Germany were occupied in the 1920s/30s. The devastating inflation took place up to 1923-24. For more info, refer to Dawes Plan. Hitler's "hatred" for minorities, particularly Jews, can be tracked in his 1924 book, Mein Kampf (recommend reading). (Speculators claim that Hitler had some Jewish blood.) Hatred of the Jews predates Hitler be several centuries and is not specific to Germany. Jews in the medieval period were the "moneylenders," as this was not considered a "Christian" profession. Envy and dislike seemed to come "with the turf." Aside from the Jewish issue, Hitler gave Germans back a sense of worth lost following War I; his government created jobs during the Great Depression (autobahn building, et al), and he "chased" the French out of Germany. I am not sure any historian can categorically explain why Hitler "hated" Jews. Remember that Hitler also persecuted other minorities and political undesirables. He must certainly have had "a few screws loose," aside from his burning drive for power.