The region that is being talked about has had a pretty chaotic history. Israel existed then basically no longer existed for over a millennium; Jewish people in the region known as Palestine - which is basically current Palestine and Israel as one land mass, e.g. the above map.
The historic demographics of Palestine indicate that Jewish people were an absolute minority in the majority of recorded history in that region:
Jewish people have been the target of anti-semitism just about everywhere on the planet since god knows when. They've been shunned in many societies for various reasons, excluded from most jobs and for example forced into jobs like money-lending and then shunned for always being money lenders. A gigantic shit sandwich for them. Then along came the notion of Zionism, late nineteenth Century: The idea that Jewish people would be better off all moving somewhere and running their own state, thus guaranteeing their rights and no longer being treated as second-class humans. A notion that at face value I sympathise with, however, since land does not just suddenly appear, they would have to pick somewhere and they got it into their heads that the place their ancestors lived like over 1000 years before is where they ought to be. A place where Palestinians already lived.
So Zionism resulted in the Jewish demographic of Palestine shifting from 3% in 1800 to 8% in 1890 (start of Zionism) to 32% by 1947 (much of which was refugee traffic post WW2). The British were still administering Palestine up to 1947 and various plans had been brought up and shelved (world wars tend to do that), but wanted to get out.
This UN proposal basically gave away two thirds of Palestinian land to Jewish people who only made up 32% of the population, unsurprisingly this was not a popular plan in Palestine, but "civilised" nations didn't want to take Jewish refugees so they ought to be dumped somewhere else to be someone else's problem, plus Zionism made Palestine a more attractive target to Jewish people.