[Abraham]

The whole problem is really a result of colonialism.

Palestine (including what is now Jordan) was promised to the Jews as a "National Home" in the Balfour Declaration (1917) by Britain, the ruling colonial power that got the Protectorate through the League of Nations. This promise was made for a strange variety of reasons. Britain first split Transjordan and gave it to Sheikh Abdullah, the grandfather of the late king Hussein. Then it promised the Arabs that there would never be a Jewish majority in what was left as/of Palestine.
In the end Britain couldn't keep it's first promise nor it's last and everybody was upset...

Finally, in 1948, the successor of the League of Nations, the U.N., decided to divide the country in equal Jewish and Arab parts and an international zone. This was accepted by the Jews and rejected by the Arabs, who started a war (War of Independence) in which they were beaten and Israel was actually enlarged.

This war caused huge refugee problems on both sides. Between 500.000 (Israel) and 725.000 Arabs left voluntarily or were forced out of the war zone and did not return. About 160.000 stayed or returned. In the aftermath of the war 580.000 Jews left Arab countries, often as refugees with their business and belongings being confiscated and immigrated to Israel, where they started a new life.
The Arab leaders on the contrary refused to settle the Arab refugees and put them in huge refugee camps, run by the UN (UNWRA) to keep political pressure upon Israel. This has been an extremely effective policy from a political point of view.