I have heard a claim that the Palestinians are descendants of original inhabitants of Israel that pre-dated even the Israelites. Is there any truth to that or any indication one way or the other according to Jewish sources?
This is a common misconception and worth clarifying.
The Philistines were an ancient people who lived in part of the Land of Israel along the coast. The Torah refers to this people as “Pelishtim”, which literally means foreign invaders, since they were a people of probable Phoenician origin who invaded the Land of Israel from the Mediterranean Sea and settled along the coast.
This people were engaged in continual warfare against the Israelites who were settled throughout the heart of the Land of Israel. There are many references to this animosity throughout the Scriptures, the story of Samson and the Philistines being one well-known example (Judges ch. 14-16).
During the next several centuries, the invading Philistines were routed, and the Jewish monarchy was consolidated over the entire Land of Israel. This period of Jewish autonomy in the Land of Israel, albeit with interruptions, lasted approximately 1000 years, culminating in the ruthless suppression of Jewish independence and ultimate destruction of the Temple by the Romans in app. 70 CE.
In order to totally eradicate the Jewish claim and presence in the Land of Israel, the Romans insidiously renamed the Land of Israel after the Jews’ early enemies, the invading Philistines, thus calling the entire country Palestina, despite the fact that even the invading Philistines had occupied only part of the coastal region alone. This is the source of Land of Israel being referred as Palestine until modern times.
It is therefore false to assert that the Arabs who refer to themselves as Palestinians originate from the Philistines. The Philistines were Phoenician not Arab. Even Arabs in Egypt are not descendants of the ancient Egyptians. Rather Arabs originate from Arabia from which they spread relatively much later on during their Islamic conquests of the Near East and North Africa. Thus they are not indigenous to either North Africa or most of the Middle East, including Palestine.
So the use of the term “Palestinian” to refer to those Arabs who migrated to the Land of Israel is actually quite interesting. If the usage refers to post-Roman times, once the Land of Israel came to be known as Palestine, Arabs are no more “Palestinian” than Jews who also lived in Palestine throughout the centuries. And if the use of the term intends to conjure ancient contexts, its usage is self-incriminating: Either because it adopts the insidious attempt of the Romans to supplant the Jews’ original and rightful claim to the Land of Israel; Or because it makes Palestinian Arabs akin to the Philistines – foreign, non-indigenous invaders of the Land of Israel.