Several nevi'im condemn the seizure of fields and houses from their owners in the starkest terms: Michah 2:1-2 denounces those who covet fields and seize them, defrauding men of their homes and their land, while Yeshayahu 5:8 condemns those who join house to house and field to field until they dwell alone in the land, and Yirmiyahu 22:3 demands that justice be done and that the robbed be rescued from the hand of the oppressor, including the ger.
Chazal and the codifiers treat robbery of property as a grave transgression regardless of the victim's identity: Bava Kamma 119a states that one who robs another of even a perutah's worth is considered as if he took his soul, and Mishneh Torah, Robbery and Lost Property 1:1-9 rules that it is forbidden to rob or oppress anyone — expressly including a non-Jew — and that the robber must return what he took. Shulchan Arukh, Choshen Mishpat 359:1-5 likewise rules that it is forbidden to steal or exploit any amount from a Jew or a non-Jew. Sotah 14a adds the broader value of walking in God's ways, who clothed the naked, as the model for one's own conduct toward others.
Shulchan Arukh, Choshen Mishpat 369:8-11 distinguishes a ruler's general decrees, which are not considered robbery when applied to all citizens equally under dina d'malchuta, from a ruler who seizes a particular individual's field or courtyard outside the law, which is deemed robbery and can be reclaimed by the original owner — a distinction about state authority over land that does not by itself resolve the status of civilian settlement or expulsion.
On the specific practical question of expelling Arab residents from the Land of Israel, the sources diverge. Gray Matter IV, Israel, Expelling Arabs from Israel argues that even poskim within the Religious Zionist community agree there is no halachic obligation to expel non-Jewish residents under current circumstances, and that there may even be a prohibition against doing so. By contrast, Rav Eliezer Melamed (Peninei Halakhah, The Nation and the Land, Supplement, Responsa of Rabbi Shlomo Goren 3) cites Rav Kook's established ruling that Yishmaelim have the status of ger toshav with rights of residence in the land, according to both the Raavad and the Rambam, addressing directly whether there is an obligation to expel today's Arab residents.
Contemporary Halakhic Problems, Vol II, Part II, Chapter IX Judea and Samaria, Settlement and Return addresses the separate halachic question of returning liberated territories, framing it as involving the scope and obligations of the mitzvah of settling the Land of Israel rather than directly resolving the question of expelling existing residents.