What an extraordinary claim. It demands an explanation. There is no part of Palestine in which Syrian law runs. There are no Syrian cops or troops in Palestine. There are no Syrian government offices in Palestine.
Throughout all of history Palestine was a part of Syria.
From the "Syria Palaestina" of Roman times all through the Rashidun, Umayyad, Abbasid, and Fatimid Caliphates, the Ayyubid dynasty, and the Mamluk Sultanate, the borders of Syria have nearly always encompassed all of what is described as Palestinian territories today, with a special exception made either for the occupation of Jerusalem by the Christian First Crusade or in the 19th century the Jerusalem Mutasarrifate of Jerusalem was split away into a special region given legal autonomy as a city-state, much like Vatican City.
All through this time, for thousands of years up through the Ottoman era, the borders of Syria included what are now described as the Palestinian territories. You can see them on a map here:
You can also check maps available on Wikipedia for the historical borders of Syria during the Caliphates, which have always encompassed Palestine.
Palestine was never an independent nation at any point in history. It was always a part of Syria, and Syria today considers it Syrian temporarily-occupied territory stolen by Western-sponsored violence and terrorism.
What an extraordinary claim. It demands an explanation. There is no part of Palestine in which Syrian law runs. There are no Syrian cops or troops in Palestine. There are no Syrian government offices in Palestine.