The Jewish immigration to Israel was a fundamental condition for the fulfillment of "the return to Zion" vision, by which the land of Israel is a refuge for the Jewish nation, in which it will renew its national existence, independence and statehood. The term 'Haapala' (Illegal Immigration or 'Aliyah Bet') symbolized the determination in carrying out the Jewish immigration despite Britain's will, which was the superpower nation. The Haapala endeavor demonstrated the determination of the Yishuv in Eretz Israel, the Zionist movement around the world and the refugees themselves, mostly holocaust survivors, in fighting for their right to freely immigrate to Eretz Israel.
The Haapala had a crucial role in the battle of the Yishuv and the Zionist movement against the British policy, which ultimately led to the establishment organization of the state. The party in charge of the Haapala endeavor on behalf of the Jewish Agency was 'Hamossad for Aliyah Bet', headed by Shaul Meirov (Avigur). About 75,000 immigrants tried to enter the country during the Haapala period. Only about 10,000 of them succeeded in illegally entering the country.
The Palmach was highly involved in the Haapala endeavor as part of its over-all activity in confronting the British and fighting for a Jewish State. The Palmach and its members were responsible for the military aspects required during the Haapala, that is: Managing the evasion of Haapala ships from the British navy at sea, protesting against the deportation of immigrants, disembarking immigrants and guiding them to shelters and sabotaging navy vessels and British facilities in charge of thwarting the Haapala. 'Hamossad for Aliyah Bet' was in charge of the Illegal Immigration to Eretz Israel during 1938–1948. 'Hamossad for Aliya Bet' enjoyed an autonomic status within the political framework of the Jewish Yishuv.