Briefly, we have a major novelty (chiddush) in this sicha, indicating that our reality is no longer limited in the way earlier generations were limited (we will see similar insights in parshas Vayigash, be”H).
Before we get to this, it is very noteworthy the Rebbe’s statement about the importance of looking at the face of the Rebbe as being included as part of learning Torah, which speeds the Geulah:
[The Geulah and building of the 3rd Beis Hamikdash] will be hastened through the study of Torah, and of Chassidus in particular. This also includes looking into the face of your Rebbe, which helps one’s understanding, as the Gemara (Eruvin 13b) quotes R. Yehudah HaNasi as saying, “This that my sharpness exceeds that of my colleagues is because I saw R. Meir from the back; and if I would have seen him from the front, I would be even sharper.”
As regards the novelty(chiddush), all students of Tanya know two things: Firstly, every single Jew must endeavor to fulfill the oath that his soul swore before coming down to the world (“Be a Tzaddik”); and secondly, as stated in Tanya, that try as one might, one may never reach this level because it is not dependent on ones merits. Some souls are born to struggle but not to achieve the goal of being a true Tzaddik (one who has overcome and transformed his evil inclination). Here the Rebbe informs us that there is now nothing standing in our way of achieving the objective! You and I, every Jew, if we will truly make the effort we can succeed to be victorious over our evil inclinations:
All this will help further purify the world and reveal G‑dliness within it. It must be accompanied by the additional G‑dly service of each particular Jew, by keeping away from evil and, furthermore, doing the utmost to fulfill the oath administered to his soul before birth, “You shall be a Tzaddik.” One might object and point out that in Tanya itself it is written that not every individual can necessarily become a Tzaddik, and that one doesn’t have complete free choice in this area. However, since the Jew has the essence of G‑d within him, ultimately even this is within his reach. Furthermore, after all the purification, etc. of the Jewish people over the course of time, now every Jew is able to reach the level of Tzaddik — similar to the way things will be in the Messianic Age.
The excuse that being a Tzaddik is “beyond my reach” and “halevai beinoni” (“if only I could reach the intermediate level”) is no longer valid! Today we are truly in a period of “I tried and I found” (“yagaati u-matzosi“).