The purge of Israel in their time of trouble is described by Zechariah in these words: “And it shall come to pass, that in all the land, saith Jehovah, two parts therein shall be cut off and die; but the third shall be left therein. And I will bring the third part into the fire, and will refine them as silver is refined, and will try them as gold is tried” (Zechariah 13:8, 9).
According to Zechariah’s prophecy, two thirds of the children of Israel in the land will perish
Actually his interpretation of Zechariah here is an overstatement of what it actually says. The "two parts therein" does not specifically constitute the children of Israel as those who will be cut off, but may very well refer to the non-Jewish element in the land, aka the Palestinians, whose numbers are swiftly approaching that "two thirds" number.
The "two parts therein" may very well constitute the Palestinian contingent (and those who are selling out their Jewish heritage), and "the third part" would constitute the Jewish inhabitants in the land brought through the fire.
The context makes it impossible for such an interpretation of the text:
"In that day a fountain shall be opened for the house of David and for the inhabitants of Jerusalem, for sin and for uncleanness."
The subject of the prophecy is the house of Israel who have defiled themselves with the idols of the nations. This is a judgment against Israel, not Palestinians.
Of course the fundamental error is in trying to apply it to yet-future events.