http://www.conceptwizard.com/pipeline_of_hatred.html
God didn't give Israel to the Jews; the United Nations did, as "restitution" for the "holocaust" suffered in Germany. Why the Arab nations were required to pay for Germany's sins is only a mystery if you truly believe in the benevolence of this world's "leaders".
(Psst. I was intentionally avoiding bringing up the question of the 6,000,000 figure to avoid any sort of revisionist arguments here, because it isn't germaine to the point I was trying to make. Assuming all the propaganda/information about the Holocaust is correct, for the sake of argument, it still doesn't make any sense for Arab lands to be handed to Jews to make reparations to "Jews" for Germany's alleged crimes. It makes even less sense in light of the likely truth that we're being lied to again by the powers that be, but I don't need to argue that here.)
As for Britain/UN... UN General Assembly Resolution 181, in 1947, coupled with the Israeli war of 1948, basically made the Israel that became Israel. Britain's earlier attempts to divide the region along religious lines never amounted to much, and it's doubtful that Britain could have made it stick (or ever really wanted to).