The Rebbe delivered the sicha below a little over a month after Yud Shevat (the Histalkus of the Previous Rebbe):
Those who say that Histalkus means that the Rebbe has forsaken us are wild people who don’t know what they are talking about.
In the Basi Le’Gani discourse—which [the Previous Rebbe] distributed in advance to be studied on the day of his Histalkus—the [Previous] Rebbe explains the statement of the Zohar, “When one bends the Sitra Achra [“the other side,” i.e., evil], G–d’s glory is revealed [estalek, which literally means “rises up”] throughout all the worlds.” Will someone come here too and interpret the word estalek literally, G–d forbid?!
Rather, the [Previous] Rebbe explains that this expression—“G–d’s glory is revealed [estalek]” represents the eliciting of a very lofty light, on the level of Sovev Kol Almin. This divine flow is called Histalkus, because it exists in an elevated state. From this we can infer that the same applies concerning the “Histalkus” of the [Previous] Rebbe. ...
Yet despite this, we want and need the Rebbe in the simple sense, down here.
The father of the Rebbe Rashab, the Rebbe Maharash, once asked his father, the Rebbe, the Tzemach Tzedek, concerning the year that had been called a “keitz” [auspicious time for Moshiach to come]: “How could it be that Moshiach didn’t arrive?” His responded, “The Likkutei Torah was printed!” the Rebbe Maharash told his father, the Rebbe, the Tzemach Tzedek, “But we want and need Moshiach literally, down here!
Toras Menachem, Vol. 1, p. 18
 Sefer HaMa’amarim 5710, p. 111 ff. 2:128b. Tanya ch. 27. Likkutei Torah, beg. Pekudei. “Encompassing G–dliness,” a sublime level of G–dliness relative to which all the differentiation between the higher and lower worlds is as naught. Torah Ohr, end Vayakhel. Printing of Chassidus is a kind of “spiritual redemption.” Chassidus reveals the greatness of Hashem, and this resembles the revelation of Hashem that will take place when the redemption arrives.
Summary: Histalkus is the term used for the passing of a Tzaddik. Although literally it means “departure,” the Rebbe explains very passionately that it should not be translated in this way when we speak of the Previous Rebbe, for the Previous Rebbe is with us no less after his Histalkus, albeit in a hidden manner. Although the Previous Rebbe is still with us, the Rebbe declares that we must not be willing to suffice with this, and concludes with a fervent prayer that we be reunited with the Previous Rebbe in a tangible, visible sense.
Lesson: The relevance of this sicha for Chabad chassidim today, after Gimmel Tammuz, is self-evident, and it is especially potent in light of the principle that the Rebbe himself taught us that “he ruled concerning himself.” The lesson is that the Rebbe is with us no less after Gimmel Tammuz, and yet we must not allow ourselves to come to terms with this situation. Rather, we must davven to Hashem and demand to be reunited with the Rebbe in a fully visible manner; or, as the Rebbe put it at the conclusion of his first Ma’amar here, “May we merit to see and be together with the [Previous] Rebbe, down here in a physical body and within our reach, and he will redeem us.”