They wanted a messiah to establish a kingdom on earth not in their hearts, and they wanted a king to free them from the Romans not to free them from their sins. Jesus wasn’t the messiah they wanted. So to a Jew, Jesus was a false messiah who claimed to be God. They hated him and killed him. We have received and believed on him. So naturally we are “enemies” according to Romans 11:28. Read Romans 11. Pretty interesting stuff.