Oh you want sources, just ask sweety, and I shall provide.
Israel should have never been in Gaza? Jews have lived in Gaza centuries before the Arabs have gone out of Arabia to conquer and occupy neighboring lands. Jews have lived in Gaza for centuries, though they were driven out by the crusaders and later by Napoleon they always resettled. Finally Gaza was ethnically cleansed by the Arabs in 1948.
for example:
The mosaic first became known to archaeologists in 1966, when the Italian journal Orientalia reported the discovery of an ancient church on the Gaza coast by the Egyptian Department of Antiquities. Within the church was a mosaic floor, described as depicting a figure of a female saint playing the harp and charming wild animals. Two pictures of the mosaic were included in the article.
When Hebrew University Professor Michael Avi-Yonah read this report, he immediately saw in the photos of the mosaic a Hebrew inscription that clearly read “David” (dywd). He correctly identified the figure as King David playing the harp and the building as a synagogue rather than a church.
http://cojs.org/cojswiki/Gaza_Synagogue_Mosaic,_6th_century_CE
It was the Hasmonean king, Yochanan, who liberated Gaza in 145 BC. He was the brother of Judah the Maccabee and it was their other brother, Simon, who sent Jews to repopulate Gaza and its environs.
In the Book of Maccabees: 1:15, it says about the recapture of Gaza:
"Not a strange land have we conquered, and not over the possessions of strangers have we ruled, but of the inheritance of our Fathers that was in the hands of the enemy and conquered by them unlawfully. And as for us, when we had the chance, we returned to ourselves the inheritance of our Fathers."
The great medieval kabbalist Rabbi Avraham Azoulai lived in Gaza where he authored his famed work,
Hesed L'Avraham, along with a commentary on the Torah (the first five books of the bible). The Jewish inhabitants made Gaza a great center of study and towns and villages from Rafah to Yavne sprung up as centers of Talmudic learning.
Many Jews fled to Gaza at the end of the 15th century where they joined the Jewish community by working in various trades after escaping from the ravages of the Catholic Inquisition.
During the 17th century, Gaza was again home to a thriving Jewish community, which boasted its share of prominent rabbis, including Rabbi Israel Najara, author of
Kah Ribbon Olam, the popular hymn sung in Jewish homes around the world every Sabbath. He served as Gaza's Chief Rabbi until his death in 1625. This century also saw the rise in Gaza of Shabbetai Zvi's pseudo messianic movement.
The great scholar, Rabbi Yaakov Emden, ruled centuries ago that Gaza is an intrinsic part of the Jewish people's national heritage. "Gaza and its environs are absolutely considered part of the Land of Israel," he wrote in his work, Mor U'ketziyah, adding, "there is no doubt that it is a mitzvah (commandment and blessing) to live there, as in any other part of the Land of Israel."
http://en.wikipedia.org/wiki/Nathan_of_Gaza