He became one of the leaders of the Jewish defense effort in Mandate Palestine and chief architect of the Haganah, the underground military organization for defense of the Yishuv between 1920 and 1948.
He emerged as one of the leaders of the Jewish self-defense movement in Mandate Palestine and chief designer of the Haganah, the clandestine military organization safeguarding the Yishuv between 1920 and 1948.