http://revach.net/article.php?id=4524

Section: Galus & Geula   Category: Eretz Yisroel
Parshas Kedoshim: Rav Zalman Sorotzkin - Whose Land Is Eretz Yisroel?
"V'Chi Yagur It'cha Ger B'Artzichem Lo Soinu Oisoi", when a foreigner lives in your land do not cause him anguish (Kedoshim 19:33).  The Iturei Torah quotes Rav Zalman Sorotzkin as saying that this pasuk comes to warn us not to be xenophobic like the extremists in of other countries and think that Eretz Yisroel is only for Bnei Yisroel with no foreigners allowed.

Eretz Yisroel was given to Avrohom who was Av Hamon Goi'im.  Every non-Jew who believes in the Hashem of Avrohom and wants to attach himself to Avrohom's children is not a foreigner in the land that was promised to Avrohom.

The pasuk adds the word "B'Artzichem" in middle, to tell us that when a non-Jew chooses to make his home in Eretz Yisroel, do not anguish him by telling him that he is living in a land that belongs to him.  If he respects the Hashem and the children of Avrohom, then it is his land as well.