The Torah describes the structure of the Mishkan in great detail, including the paroches which separated between the kodesh ha'kodoshim and the heichal. The expression used in the chumash is, "...v'hev'dela haparcohes bein hakodesh u'bein kodesh hakodoshim" (Shemos 25:33), i.e. that the paroches should separate between the kodesh and the kodesh ha'kodoshim. This year erev Pesach will be on Shabbos and when we recite kiddush at the seder on the first night of Pesach we will also recite havdalah. The beracha at the end of havdalah will conclude, "hamavdil bein kodesh l'kodesh", a blessing to Hashem who distinguishes between kodesh and kodesh ha'kodoshim. The premise of the entire Sefer Avudraham is that all tefillos are to be recited in a biblical Hebrew[1], and he comments that the Biblical source for that expression is in the possuk mentioned above, that the role of the paroches was to separate between the kodesh and kodesh ha'kodoshim.
In the realm of mitzvos, we have a very detailed hierarchy: tefillin have a higher level of keddusha than mezuzah, tefillin shel rosh have a slightly higher level of ksddusha than teffilin shel yad, and a sefer Torah has a much higher level of keddusha than tefillin. Hashem is the source of keddusha and the entire creation that emanates from him has keddusha as well. Therefore, when we say that a mezuzah has keddusha, we mean to say that it has a higher level of keddusha than the rest of the world. Just as it is important to keep in mind that there is a big distinction between koddesh and chol, so too it is equally important to keep in mind the difference between koddesh chamur and koddesh kal.
The Ramban in his introduction to chumash Shemos writes that Sefer Bereishis deals with all of the beginnings: the beginning of the world, the beginning of mankind, and the beginning of the Jewish people. By the time we complete Sefer Bereishis, we have already been introduced to Avraham, Yitzchak, Yaakov and the twelve shevatim. Sefer Shemos, the Ramban explains, tells of the first galus of the Jewish people and the geulah therefrom. One may wonder how the Ramban can say that Shemos tells about the geulah if the Jewish people don't return back to Eretz Yisroel until after the death of Moshe Rabbeinu. The crossing of the Yardein to enter Eretz Yisroel appears in Sefer Yehoshua, not in the chumash, because Moshe Rabbeinu was not permitted to enter Eretz Yisroel. The Ramban responds to this question that although it was tragic that the Jews had not returned back to Eretz Yisroel yet, at the end of Sefer Shemos there are the four parshas (Terumah, Te'tzaveh, Vayakheil, Pikudei) which describe the Mishkan in detail. The primary tragedy of galus Mitzrayim was not that the Jews were no longer living in Eretz Yisroel but rather that our ancestor Yaakov Avinu had no longer hashro'as ha'Shechina. At the time that the Mishkan was built, the Shechinah returned and that was the true geulah. It is possible for people to live in chutz la'aretz and still be in a state of geulah, and it is possible for all the Jews to live in Eretz Yisroel while not having a geulah.
The Chazon Ish lived in Vilna during the last years that he was in Europe, and he moved from there to Eretz Yisroel years before World War II. In the biographies of the Chazon Ish it is quoted in his name that the upon the occasion of ha'komas ha'medinah in 1948, the Chazon Ish commented that we are now experiencing the end of the galus but we still have not attained the geulah. Many did not understand his comment and thought it was merely double talk. What he meant by that statement was that now the Jewish government in Eretz Yisroel is inviting and encouraging all the Jews from all over the world to come to Eretz Yisroel, and in that sense the galus is over, since no one is forcing us to remain in chutz la'aretz. But we still have not experienced any hash'royas ha'Sechinah, and thus have not attained the geulah.
On Tisha B'av there is a very old minhag quoted in Shulchan Aruch that we remove the paroches from the front of the aron kodesh. The paroches in the Beis Hamikdash served the purpose of separating between the Shechinah, which was in the kodesh ha'kodoshim, and the heichal. On Tisha B'av we are commemorating the fact that the Shechinah left the kodesh ha'kodoshim. The Gemarah (Rosh Hashana 31a) tells us that the end of the period of the bayis rishon it was visible that the Shechinah left the kodesh ha'kodoshim in ten stages till it went back to heaven. We remove the paroches in shul to symbolize the fact that the Shechinah is no longer there where it is supposed to be, and therefore there is no need for a paroches to separate.
We pray to Hashem every day to hasten the geulah. The chachomim had a tradition that milchamos are aschalta d'geulah. May the milchama currently taking place in Eretz Yisroel be the last milchama in the world and may we all be zocheh to see the four parshiyos (Terumah, Te'tzaveh, Vayakheil, Pikudei) fulfilled with the complete geulah.
[1] Not all agree with this premise of the Avudraham. The Netziv on his commentary on the Sheiltos was of the opinion that the Gemarah does not seem to agree with this idea.