An Ancient Hatred Examined
Anti-semitism is hostility toward or prejudice against Jews as a religious, ethnic, or racial group, which can range from individual hatred to institutionalized, violent persecution. The root word "semite" comes from the name of Noah's son, Shem. Technically, a Semite is anyone who comes from the family of Shem, which includes most of the Middle Eastern peoples. However, Semites are typically seen (in the eyes of the world) as being only Jews, and not Arabs, Iraqis, Persians, or others.
Where did anti-semitism originate? Biblically, it was created in the heart of Satan, and can be better defined as "hatred for God's chosen nation/people". Anti-semitism can be both racist (even though skin color doesn't really play a part) and anti-Judaistic in nature. The Jewish people have been more systematically persecuted and exterminated like no other people group on the face of the earth. And it hasn't just happened once or twice in history, but many times in many different countries.
One of the clearest proofs that anti-semitism is Satanic is to study the Bible and take note of how often God makes a promise of someone being in the messianic line, and Satan's following attempts to wipe out that person or their line. These focused persecutions began with Abraham, then Isaac, then Jacob, then David, then Solomon, and all the way through Jeconiah, in which God Himself cut him off from being the "human" line from which Jesus would come. Jesus' royal line was through David's first son, Solomon (the ancestor of Jeconiah), but His human line was from Nathan, David's second son.
In the Bible before Christ was born, it's understandable why anti-semitism existed: to prevent Jesus from being born and saving both His people and the world. But now that Jesus is born, died, and resurrected, why does anti-semitism still exist? Some of the reasons are that God has given many promises to the Jews which have yet to be fulfilled (and Satan still wants to thwart them) AND that the Jews are STILL God's chosen people/nation, though He had set them aside for a time during the Diaspora (the world-wide scattering of Israel).
Sadly, most denominations of the Church hold anti-semitic views, and Jewish persecution has been ordered from the highest offices of the Church. Even today with Israel restored as a nation, most churches preach that the Church has replaced Israel in God's plans, and thus has inherited all the rights and promises that God gave to Israel. But God means what He says and says what He means, and when He says "Israel", He means Israel!
Anti-semitism as a Prophetic Alarm-Clock
From the Bible, Satan seeks to thwart God's plans, regardless of what they are. And since Satan cannot "hurt" God, he has to settle for the next best thing: hurting the people God loves. From Genesis to Revelation, everytime God blesses a person or family (or nation), Satan tries to undo or disrupt the blessing. However, from time to time, Satan uses a king or nation to try to wipe out the Jewish people, and typically he raises the levels of anti-semitism just before prophetic events are about to be fulfilled.
A recent example of this is that Israel was prophecied to be restored as a nation in 1948 after a long exile, and Satan raised Hitler to power to wipe out over 1/3 of the Jewish population only a few years before they could return. Satan can read the Bible prophecies and run the numbers as well as you or I can, and he probably figured out that God would begin to restore the nation sometime in the mid- to late-1940s, so he started working quickly and ruthlessly to thwart the restoration by the Holocaust. Consider all the time and effort Hitler put into the Holocaust -- were the Jews ever really a threat or a problem to him? Of course not -- the Jews were very peaceful and beneficial in the nations where they were scattered.
One way of tracking how close we are to the next Biblically-significant event is to watch whether anti-Semitism is on the rise or on the decrease in the current news events and media. If we see an increase in anti-Semitism around the world, we should be more watchful for another significant Bible prophecy to be fulfilled. And the one that most Bible students have been watching for since June of 1967 is the Magog Invasion of Ezekiel 38-39...