What did Martin Luther believe about the Jews and why?

Martin Luther was a detester of the Jews from a religious perspective, because he believed they had killed the Messiah. Scripture does not support that view; although he may have had other good concepts, he was far off on this point.

Les explains that Martin Luther was a detester of the Jews, likely from a religious point of view, because he felt they had killed the Messiah. Les stresses that this view is not according to Scripture, and that while Luther may have come up with many other good concepts, he was 'sure and left field' on that one. This relates to Paul's emphasis in Romans 10: God is not through with the Jew, despite Christendom's opinion that He is because they rejected their Messiah. Jew and Gentile are alike under sin, both need salvation, and there is no difference.

Was Martin Luther right in his view of the Jews as Christ killers?

No. Martin Luther's view that Jews were Christ killers and that God was through with them is not according to Scripture. Paul teaches Jew and Gentile alike are under sin and in need of salvation, with no difference; salvation is offered on the same level playing field.