The Balfour Declaration was the relation of the British government's sympathy to the Zionist's insistence on a Jewish state in Palestine, but the lobbying efforts predate that declaration by decades, not just in Great Britain, but Europe.
Here's the text:
Foreign Office
November 2nd, 1917
Dear Lord Rothschild,
I have much pleasure in conveying to you, on behalf of His Majesty's Government, the following declaration of sympathy with Jewish Zionist aspirations which has been submitted to, and approved by, the Cabinet.
"His Majesty's Government view with favour the establishment in Palestine of a national home for the Jewish people, and will use their best endeavours to facilitate the achievement of this object, it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine, or the rights and political status enjoyed by Jews in any other country."
I should be grateful if you would bring this declaration to the knowledge of the Zionist Federation.
Yours sincerely,
Arthur James Balfour
Of course no one believed that turning an entire region over to, not just Jewish control, but ownership was going to happen overnight or be well received by those who've lived there for generations. But the Zionists said, sure. Wink-wink.
Less than 7% of the land we call Israel was fairly purchased. 56% was confiscated, and the rest gained in wars resulting from implementation of the British Mandate and UN resolutions.
The Palestinians don't hate Israel for no reason. And Iran has taken up their cause.
But the Zionist movement began with Jewish elites. And Palestine wasn't the first suggestion of the British Government. Britain offered regions in East Africa, Cyprus and Argentina for a sovereign Jewish state...none with the complications inherent with Palestine, and some in the Zionist movement, I've found out, were in favor in one or more of those. But no, the elites insisted on Palestine, because of its "historical and religious significance."
They want it for the Temple site, among others. Motivations differ on the part of religious and secular Jews, naturally. Religious Jews and ignorant Christians think that Jews still have a divine right that land, and that God wants to be worshipped by Jews in a temple there, and the secular Jews are quite content with that sentiment for the authority it lends them and the loyalty it fosters.