Arabs moved to this area ("occupied" is the word you seem to like) when the Filisters of Kenaan were long gone. Not that this historical fact should have any influence on today's issues. Land in the (most of) West Bank belongs to Palestinians because they live on it NOW, irrespective of the fact that Palestinian nationality was only created in 1967 (before that they all called themselves Jordanians and had Jordanian passports).
Opposition leader Isaac Herzog to speak at anti-violence rally in Tel Aviv on Sat. night (Haaretz)
from the article: Al-Qaida No. 2 blasts Arab leaders for 'surrendering' to Israel