The Balfour Declaration was one of the most blatent acts of perfidy and outright dishonest double-crossing in modern history. At the SAME TIME that the British promised that they would uphold the rights of Arabs to self-determination - in return for the Arabs fighting (and defeating) the Ottomans - they also effectively bartered away land that WASN'T THEIRS to a 3rd party - the Zionists.
This was all in response to someone trying to pass off the above act of basic dishonesty as legitimate authorisation for Israel, and every bit of nonsense that has followed.
The only authorisation that "Occupied Palestine" (aka Israel) ever had, from a moral perspective, was the old story of white European has guns, white European wants your land, white European will come and take it.
Whatever the reason for why the Europeans wanted it (resources, more space, or "our holy book says it belongs to US") really doesn't matter. The whole thing is a sham, which is why 60 years after the fact and after countless beatings, you still haven't "convinced" the natives that you're right.
And while we're all lecturing each other about the finer points of history, might I point out that this isn't the first time that Europeans came and took that strip of territory from the locals. And eventually, the locals took it back, lock stock and barrel ....