Do you know what was going on at the time? Jews immigrated mostly to avoid death in Europe from the pogroms and the holocaust. The Arabs could have welcomed them and, in fact, many did, but some decided to fight, even though the immigrants were there legally, bought land, and hugely benefitted the local economy -- in fact, many Arabs immigrated to take advantage of it. And keep in mind that it was not an Arab state -- there was no state named Palestine. There were Arabs there, both Christian and Muslim, and Jews, as there had been for thousands of years. They are, after all, the same people.