The bulk of Parshas Bamidbar and much of Parshas Naso address the counting, or more correctly, the recounting of the Jewish people, the first count having taken place during the first year after the Exodus in preparation for the construction of the Mishkan. Many of the commentaries (see Rashi, Ramban, Ralbag, Malbim and others) attempt to explain the necessity of a second count and highlight various differences between the two censuses.
One difference noted by Rashi and Malbim concerns the addition of the phrase, "lemishpechosam leveis avosam - according to their families, according to their fathers' household" (1:2,18) which does not appear in the description of the first count in Parshas Ki Tissa. Rashi explains that each Jew had to produce evidence as to which family he belonged. The purpose of this, Malbim elaborates from Chazal, was that since the Shechina, the Divine Presence, was about to rest in the Mishkan amongst Benei Yisrael, it was necessary to establish the precise family lineage in order for this to occur.
Perhaps we can expand upon the significance of the mention of the family unit specifically at this point. Chumash Bamidbar is referred to by Chazal as Chumash HaPekudim, the parallel Hebrew phrase to the well-known English title of this section of the Torah, the Book of Numbers. Commentaries note that although Seifer Bamidbar as a whole contains much more than the commandment to count the Jews, the two parshiyos describing two separate counts, our parsha and Parshas Pinchas, serve as crucial points in the seifer. In our parsha, the generation of the Exodus is counted; in Parshas Pinchas, after the tragic episode of the Meraglim (the spies), in the aftermath of which the entire adult generation of the Exodus was punished with premature death in the desert and the loss of the right of entry into the promised land, their children, who in the interim had grown to maturity, were counted. Thus, the two tallies serve to emphasize the unifying theme of all the disparate episodes contained in this chumash: the transition from the Dor HaMidbar, the generation of the Exodus, to the Dor Ba'ei Ha'aretz, the generation of those that entered Eretz Yisrael.
However, as described in Parshas Beha'aloscha, the first generation was about to enter Eretz Yisrael and, had they not sinned, would have done so very soon after the construction of the Mishkan. Consequently, it is not surprising if some of the differences between the original counting of the Jewish People in Parshas Ki Tissa, when they had just left Mitzrayim, and our Parsha, when, a year later, these same people were poised to enter the Holy Land, can be explained based on this very distinction. Malbim, for example, notes that the phrase "letzivosam" - according to their legions", is stressed in the count in our Parsha because of the need to take a tally of those fit for the upcoming battle of conquest in Eretz Yisrael in addition to ascertaining the number of all those over twenty. (Miraculously, the number fit for battle was identical with those over twenty; none were weak or otherwise incapacitated.) Similarly, the emphasis on the family can be explained. During the initial stages of Kelal Yisrael's stay in the Midbar, the family as a vehicle of transmitting the message of Toras Hashem was not as crucial. The entire nation witnessed the Exodus, had seen G-d reveal Himself at Har Sinai and address the Jewish Nation through giving them His holy Torah, and were all centrally located around the revealed Divine Presence in the form of the Ananei HaKavod. The generation entering Eretz Yisrael, by contrast, destined to settle eventually in the diverse towns and villages and even isolated farms of their land, not all near Yerushalayim, the place of the revealed Shechina in the Beis HaMikdash, had to look toward the family unit as the main source of the Masorah begun in the desert. However, had things proceeded according to the original plan, as Midrashim indicate, had Moshe led the Jews into Eretz Yisrael, the Beis HaMikdash built would have been eternal and the miraculous, not the natural, would have been the norm. Hence, inspiration and direct, revealed connection to the Divine, although less concentrated than in the Midbar, would still be apparent and readily available. Hence, the family's role in conveying the Masorah, while to be more central than in the Midbar, would not be the sole method.
After the sin of the spies and Kelal Yisrael's spiritual descent, after Moshe and Aharon too had lost their privilege to enter the Holy Land, and Yehoshua was to lead the new generation of the Jewish People into the Land and under whose leadership the Temple would not be built, although there were certainly open miracles during the initial stages of conquest, these gradually lessened to introduce a more "natural" order of events. In this environment the family's role in instructing the next generation concerning the message of Hashem's ultimate Existence, His omniscience and omnipotence, and His revealed word and mission for the Jewish People, and through them for all of mankind, rose to a position of even greater prominence. Hence, in Parshas Pinchas, not only is the family stressed in the counting, but each family is mentioned, almost redundantly, for example, "Chanoch misphachas haChanochi, L'Palu mishpachas haPalu'i - Chanoch, the family of Chanoch, to Palu, the family of Palu" (Pinchas 26:5), etc. The Jewish parents would now be charged with the central mission of passing the Masorah over to their children, all the more crucial in the absence of open miracles and revealed Divine Presence in the immediate vicinity of the Jewish places of residence. Thus "mishpachos" (families), although not mentioned at all in the initial count due to the unique midbar experience where the family role was less essential, are highlighted more during the count of the original generation about to enter the Land of Israel, and are emphasized even more during the count of the second generation about to enter Eretz Yisrael. These changes were perhaps due to the progressively more central role the Jewish family would have to assume in order to preserve dedication to the Torah and its ideals in the subsequent generations.
Certainly in times of exile when, due to our sins, there is no revealed Divine Presence even in the Mikdash, and all the more so in a period of rampant materialism, atheism, agnosticism and many other "-ism's" which attract so many of our youth and which detract from or eradicate, chas veshalom, the message of Torah, the crucial educational role of the Jewish father and mother is more important than ever. It is insufficient to entrust our children's education to teachers in yeshivas alone. Jewish parents, whether by text or by example, are charged with the sacred task of "v'limad'tem es b'neichem." As Rav Farber mentioned to me recently: "Veshinantam levanecha - and you shall teach your children", commands the Torah. How? Through "vedibarta bam beshivt'cha beveisecha uvelecht'cha baderech uv'shachb'cha uv'kumecha"; through your speaking about the words of Torah in your homes, in your places of business, and on the road, by assuring that Torah and its mitzvos permeate every aspect of your encounters with the world, this assures the continuity of Hashem's message started at Sinai until His Word is once again openly revealed in the times of our redemption.
May Hashem grant us the special gift given to Betsalel, the architect of the Mishkan, "u'lehorot es Benei Yisrael" (VaYakhel35:34), not just to be able personally to develop spiritually but to fulfill our roles in transmitting the Mesorah to our children as well.