Islam teaches that Palestine is the land of the prophets, and Muslims consider the land to be holy. Judaism teaches that this was the land for the descendents of Moses to live in peace. While the conflict can be traced back to Biblical and historical accounts of the Jewish exodus from Egypt and the subsequent wars between the Hebrews and the Philistines, Assyrians, and Palestinians, it's current roots began after World War II.
The idea of a sovereign State of Israel was established when the United Nations voted, on November 29, 1947, to separate British controlled Palestine into two countries. There was opposition to a dual national state, so the ideal of partitioning the country into Jewish and Palestinian states was agreed upon. The Palestinians forfeited an opportunity to recognize the UN plan and establish a state of their own. The King of Jordan controlled the West Bank and the divided Palestinians could not agree how a central government for themselves. While the Palestinians owned the land for centuries they refused to recognize that an organization had a right to take it from them and give it to others. The Palestinians organized themselves in communities and did not have a strong central government capable of creating a standing army, or creating an administration capable of governing themselves. .
The majority of the Jewish population lived in the urban centers of Tel-Aviv, Jaffa, Haifa and Jerusalem. The Jewish population was small compared to the population of Palestinians. The UN resolution invited Jews from other countries, mostly displaced from Germany to come and settle in the British controlled Palestinian territory. Israel was awarded the most valuable territory, fertile lands along the coast and the major seaport of Haifa. The resolution created an atmosphere where the new country of Israel began to take action to assure its viability. Once the United Kingdom abandoned its control in Palestine there was no neutral authority capable of preserving peace and order.