[The discourse presented here was edited by the Rebbe and printed for Beis Iyar 5751 (1991), and with retrospect we can see how it is 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 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).”
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 seemingly 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 the 6 higher sefiros and the 7th (in the language of kabbalah Z”A and Malchus (ז”א ומלכות) which are likened to husband and wife) . Thus the word נפקדת also means the union which can bring forth children, relating to the union of husband and wife. This unification of the sefiros takes place through the intellectual attribute of Bina, which is from a higher level. This can be read as a hint to what the Rebbe describes as the “direct way” to bring the Geuloh in actuality: by learning (the power of Bina) the subjects of Moshiach and Geuloh.
Further, the Rebbe explains how the name נתן (last three letters of Yehonosan) refer to Malchus on the level described as sea (ים, which conceals the sefiros), whereas Dovid is Malchus on the level described as dry land (ארץ, where things are revealed). The verse “Yehonosan said to him [to Dovid]…” refers to transforming the sea to dry land (as occurred at the spitting of the sea). Interesting to note that the gematria of the words in the verse of crossing the sea — ויבֹאו בני ישראל בתוך הים ביבשה — has the same value as the declaration יחי אדוננו מורנו ורבינו מלך המשיח לעולם ועד. (Which was declared before the Rebbe for the first time on the Shabbos following the release of this maamor in 5751!)
All of the above is in connection with Erev Rosh Chodesh, when the moon is concealed. This reflects a state of complete self-nullification (bittul) which brings about the birth of the new moon on the following day: the unification of the sun and the moon (mashpia and mekabel). How can the bittul of Erev Rosh Chodesh accomplish this amazing unification? Because the bittul of the time when the moon is concealed draws down from the level of Kesser (כתר), the level which is entirely above the chain of worlds (סדר השתלשלות).
Look closely: a period of concealment which appears to be quite a negative phenomenon is actually a time when the highest levels are being drawn down! This is in order to bring about the Divinely desired unification of mashpia and mekabel (Hashem and Yisroel, Rebbe and Chassidim) through the power of Bina (learning and understanding). This learning and understanding brings about the internalization of the lofty levels that are drawn down at the time of concealment — an experience which is likened to the splitting of the sea, when the concealment itself is transformed to revelation (and the verse has the same gematria as the declaration of “Yechi Hamelech…”) (Can we sense that the Rebbe is explaining for us what is happening b’pnimiyus as we live through the “Erev Rosh Chodesh” of the post Gimmel Tammuz era?)
Returning to the maamor, 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 giving of power (נתינת כוח) for the union (נפקדת) 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 avoidah that takes place in a situation of concealment — avoidah that brings about a revelation of the unification of the mashpia and the mekabel and an end to that very concealment itself!