The haftorah that is read when Shabbos falls out in Erev Rosh Chodesh (the day before the new month when the moon is completely concealed) begins with the verse: “Yehonosan said to him: tomorrow is [Rosh] Chodesh and you will be remembered (נפקדת) because your place will be vacant (כי יפקד מושבך).”
A discourse was edited by the Rebbe and printed for Beis Iyar 5751 (1991) explaining these words, and with retrospect we can see how they are meant to guide us and strengthen us through the present time (even more so than when it was published), as will be explained, בע”ה.
The words of this verse demand explanation: why are words from the same root — נפקדת and כי יפקוד — used for completely opposite concepts? “You will be remembered” is quite the opposite from “your place will be vacant”, which implies that he will be missing.
To explain this, the Rebbe mentions several concepts which we will touch upon here only superficially (but the wise will investigate and find deeper things…).
Firstly, the Rebbe explains that the entire “drama” in this haftorah involving Shaul Hamelech, his son Yehonosan, and Dovid Hamelech are on a deeper level referring to the unification of Z”A and Malchus (thus the word נפקדת also means the union which can bring forth children). This takes place through Bina, which is higher than both. This can be read as a hint to what the Rebbe describes as the “direct way” to bring the Geulah in actuality–by learning (the power of Bina) the subjects of Moshiach and Geulah.
Further, the Rebbe describes how the name נתן (last three letters of Yehonosan) refer to Malchus on the level described as ים sea (which conceals the sefiros), whereas Dovid is Malchus on the level described as ארץ dry land. The verse “Yehonosan said to him [to Dovid]…” refers to transforming the sea to dry land (as occurred at the spitting of the sea קריעת ים סוף). Note that the gematria of the words in the verse of crossing the sea — ויבֹא בני ישראל בתוך הים ביבשה — is the same as יחי אדוננו מורנו ורבינו מלך המשיח לעולם ועד.
All of this is in connection with Erev Rosh Chodesh, when the moon is concealed. This reflects a state of complete bittul (self-nullification) which draws down from the level of Kesser כתר which is entirely above the chain of worlds סדר השתלשלות and brings about the birth of the new moon (the next day) which is the unification of the sun (mashpia) and the moon (mekabel).
In other words: a period of concealment which appears to be quite a negative phenomenon is actually drawing down the highest levels in order to bring about the Divinely desired unification of mashpia and mekabel. How? Through the power of Bina (learning and understanding, which brings about the internalization of the lofty levels that are drawn down via the concealment) during the experience which is likened to Kriyas Yam Suf — transforming concealment itself to revelation, and the declaration of “Yechi Hamelech…”
Furthermore, the verse starts with the words “And Yehonosan said” (the drawing down of the lofty lights of Atzilus) and them is followed by “tomorrow is [Rosh] Chodesh”, meaning Erev Rosh Chodesh when the moon is in a state of concealment. First the lofty lights are given, after that the concealment takes place. (First the lofty lights of the Sichos of 5751-52, as a preparation for the concealment of 27 Adar and 3 Tammuz.)
In fact, the Rebbe explains that in the path from coming out of Mitzrayim (in Nissan) to Matan Torah (in Sivan) Erev Rosh Chodesh occurs twice, for the months of Iyar and Sivan. Erev Rosh Chodesh Sivan is a נתינת כוח giving of power for נפקדת, the union that occurs via the giving of the Torah. Erev Rosh Chodesh Iyar (when this discourse was originally said) is a נתינת כוח giving of power for ויפקד מושבך — the time of concealment, as described at length above.
Learning the discourse itself will surely help the reader to put all these concepts in their proper place, and understand how the Rebbe (in this discourse and in many of the Sichos of this period) is preparing us for the crucial avodah that takes place in a situation of concealment — avodah that brings about a revelation of the unification of the mashpia and the mekabel and an end to that very concealment itself!