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Short answer
Simply put, Jews did not steal lands from Arabs. Most of it was bought legally, and some of it was won and transferred in the war in 1948 (which was forced on Israel by Arab countries!)
Long answer
Before the State of Israel was established in 1948, Jewish immigrants settled in vacant areas and in most cases purchased land outright from the legal owners. When Arab militaries attacked Israel in 1948, Israel annexed some of the land of the countries that lost the war. This is no different from any territorial change due to wars, and such examples occurred in WW1 and WW2. It’s also important to note that Jews lived in communities throughout the land of Israel for thousands of years, so it’s simply not possible for them to steal their own land.
