There are some in the world of Torah Judaism who will not participate in any "Redemption" activity. They will sit and wait in the Diaspora for the Moshiach to magically appear and take care of everything. There are others Torah observant Jews who claim that everything, from gathering in the Exiles to building the 3rd and Final Temple is possible through human effort (Obviously, effort blessed by G-d) My question is - how much should I physically work towards the Redemption? How much should I sit back and wait for Moshiach to come and take care of "the rest"? If Israel allowed it tomorrow, can we, and should we, rebuild the Temple immediately?
R. Pinchas of Vilna in his book Sefer Habrit (Part I, Essay 9, Chapter 16) writes that a person should have intention when fulfilling the Mitzvot to hasten the redemption of Am Yisrael. Rav Hillel of Shiklov, (the disciple of the Vilna Gaon, Hagaon Rav Eliyahu, also known by the acronym Gra) compiled a list of things the Vilna Gaon told him which must be done to bring about the Ge'ula. It appears in the book "Kol Hator", chapter 5 (in the edition in my possession it is printed together with the book "Hatekufa Hagedola," by Rav Menachem Mendel Kashher, zt"l) Based on the Gra, Rav Hillel spoke of a concept called "Harchava"= Expansion. This expansion refers to physical expansion of Eretz Yisrael and of course a spiritual expansion. There you can find other aspects and details of what is incumbent upon us to bring about the Ge'ula. On a simpler plain, every Jew who lives in Eretz Yisrael and makes a positive contribution to his or her community by establishing a family and a home here and having community involvement and commitment is contributing to the Redemption. In regard to the building of the Bet Hamikdash: The building of the Bet Hamikdash is one of the tasks of the Mashiach according to the Rambam. On the other hand, some sources say that the future Bet Hamikdash will come ready from Heaven. The Mashiach will have arrived by then, so I guess we will have to wait and see. However, The Chafetz Chaim had said that we have to be prepared for the building of the Mikdash. He therefore instructed to study the laws of the sacrifices, so that when the Bet Hamikdash is built will be ready. May that be speedily in our days.