This question has been asked throughout ages without any definitive answer. Thus, it behooves us to first take a look at some previous attempts and understand where they fail. Previous attempts take a look at any number of possible causes individually; one at a time. There are six primary commonly proffered causes which are: economic, 'the chosen people', scapegoating, deicide, being outsiders, and racial inferiority. Authors will typically try and focus on one cause at a time and find some time in history when it was absent and anti-Semitism persisted and thus disprove it as a cause. The flaw in any such analysis is result of perceiving anti-Semitism as a single-cause effect.

Like so many things in world, anti-Semitism is a multi-causal effect. That is, you can't remove any one cause and remove effect of anti-Semitism. Human height is determined similarly, as a multi-causal (polygenic) trait. There are many genes (units of inheritance) that determine human height, all of which interact with one another. Thus simply turning off one gene for human height has complicated effects on overall resulting height of any given person. This multi-causal type analysis must be applied to anti-Semitism in order to yield any meaningful results.

Anti-Semitism should be conceived as a tree of causes and effects. At root of that tree is a societal need for an underdog. What started tree growing was one of proffered causes: 'the Chosen People'. I'm reminded of story my father tells from his youth. He went around neighbourhood proudly announcing that he was Superman. One of older boys decided to challenge his claim and threw him straight over a fence saying: "If you're Superman, let's see you fly!" My father landed face first in dirt laying his claim to rest.

Like older boy was to my father, Roman Empire was challenger to Jewish empire's claims of being chosen people of God. The Roman Empire conquered many peoples throughout its existence, but none with 'pomp and circumstance' embodied in 'Judea Capta' coin, coined to celebrate victory of Roman Empire over 'Chosen People'. (http://www.bible-history.com/sketches/ancient/judea-capta-medal.html)

The defeat of Jews at hands of Romans set off a host of effects which themselves, historically, also became causes of anti-Semitism. As a dispersed people we were outsiders in many countries of Diaspora. Persecution of outsiders and using such people as scapegoats is a side effect of predatory instinct. The 'proud' lion of animal kingdom doesn't attack leader of pack wildebeest but instead attacks weakest of herd. Likewise in human relations, we tend to pick on people with least chances of mounting an effective reprisal. Thus we see that chosen people quickly became people of choice when it came to choosing a scapegoat.

Jeremiah 33.3 "Call unto me, and I will answer thee and shew thee great and mighty things, which thou knowest not."

It was late Saturday evening on that hot and humid August day in 1987. The Lord had saved me in January 1987, and He had already used me greatly. That evening, I had read above scripture, and Lord began to reveal unto me great and mighty things. One of first spiritual gifts (1 Corinthians, Chapter 12 verses 1-10) had imparted unto me was gift of faith. Another was gift of discernment of spirits. He had also been teaching me how to pray, and I had already seen glorious answers to many prayers. The Lord had also been teaching me how to come against evil supernatural forces.

Earlier, Lord had used me to rebuke evil spirits. The first time this happened to me was at an old house in south Georgia. I was sitting in my office at Fort Stewart (I was in Army at that time), when Lord spoke to me and told me to go to Ludowici, a small town nearby. I immediately left my office, and drove to town. When I arrived, I asked Lord where to go, and He directed me to an old two story house down a side street. I parked my car, took my Bible in my hand, and went and knocked on door. A woman opened door, and I asked her if she had been experiencing any abnormal problems. With a look of amazement, she replied, "Yes, there is a room upstairs that has all kind of noises. We have nailed door shut and it still has come open. My son tried to stay in that room but is was cold, and he was afraid of noises." When she spoke these words, I sensed presence of great evil. The hair of my flesh stood up (Job 4 verse 15 "Then a spirit passed before my face; hair of my flesh stood up:"). With Bible in hand, I told woman Lord had sent me there to get rid of that evil presence. As I began to walk up stairs, I started calling on name of Jesus and pleading power of shed blood. The great darkness and sense of evil almost overwhelmed me. I entered room and began to come against evil, saying "At name of Jesus, devils have to flee. At name of Jesus, we have victory." My skin was crawling and my hair was sticking straight up. After several minutes of intense prayer and agony of soul, evil fled, and I experienced a great peace that passes all understanding. The Lord spoke to me and said, "Mission accomplished." As I left house, I told woman that things were now okay. Several weeks later, I was reading about history of town of Ludowici. I read where two women were murdered in that room in that very same house where I had went earlier!

The Lord used me in other ways, also...He was training me for greater things.

In mid May, 1987, Lord spoke to me and told me to go to Jekyll Island, Georgia. He showed me which motel to stay at but told me not to check in until later. The island is beautiful and has a storied history. Originally, it was owned by very wealthy and they used it as a winter retreat. Some of original houses are still there, restored to their former glory. Now, state of Georgia owned island.