Is conquest of the land of Israel considered to be theft?
Your question is the topic of the first Rashi in chumash. Rashi says that the reason why the torah starts with the creation of the world, is to justify the fact that the Jews conquered Eretz Yisroel. Just in case the nations of the world will say that we “stole” the land from the Canaanites, the torah is telling us that H-shem created all of the land, and He took it away from them and gave it to us, as it is stated, because He gave it to Avrohom. There are also numerous times that the term inheritance is used in reference to the Jews inhabiting Eretz Yisroel.