The above stamp on the left was the original postage stamp issued by the Brittish Mandatory Government that occupied the Land Of Israel until the War of Independence in 1948. Notice that in the lower left corner the words "Palestine" are in Hebrew followed by a parentheses in which an aleph-yod is placed, circled in red on the right stamp. This aleph-yod is the abreviation for "Aretz-Yisrael" i.e.: the "Land of Israel".
The stamp shown above has been very recently issued by the Palestinian Authority for their postal service in the areas they occupy in Judea, Samaria and Gaza. It contains a reproduction of stamp that was once in use during the British Mandate of Palestine in the early to mid-20th Century. The PLO has done the same with two other British Mandate stamps, the Dome Of The Rock on the Temple mount, and David's Tower featured below.