The Arab Muslims hate the Jews because they're Jews. The Jews hate the Arab Muslims for hating the Jews just because they're Jews.
This is an extreme oversimplification of a decades-long geopolitical--and also partially religious--conflict. There is a lot of antisemitism in fundamentalist Islamic thought (which not all Muslims subscribe to in the first place), but there's also a lot of legitimate criticism concerning Israel's violations of international law mainly by building illegal settlements and committing war crimes.