After the Golden Calf, Moshe gathers the people for a discourse:
וַיַּקְהֵל מֹשֶׁה אֶת כָּל עֲדַת בְּנֵי יִשְׂרָאֵל וַיֹּאמֶר אֲלֵהֶם אֵלֶּה הַדְּבָרִים אֲשֶׁר צִוָּה ה’ לַעֲשֹׂת אֹתָם’ – Moses gathered the whole community of Israel to assemble, and he said to them: “These are the things that the Lord commanded to do” (35:1)
He tells them certain laws of Shabbos, and collection for and initiation of construction of the Mishkan.
This occurred the morning after the Yom Kippur Moshe returned with the second Luchos. It seems likely that his first public appearance upon his return would include a notable message regarding their conduct. Yet he gathered them together to discuss Shabbos and the Mishkan. The Nesivos Shalom notes out how usually, an act, speech or instruction initiate an episode; this is the sole instance where וַיַּקְהֵל , getting people together, starts a story.
The Noam Elimelech explains that mitzvos were given to the nation, not individuals. This means that when a person sins, it is an act of rebellion, splintering from the nation, albeit momentarily. Redemption and forgiveness is attained by blending back into the nation. In the same way a harmony is a beautiful sound where no single voice is discernible, a tzibbur, the collective, is safe because an individual does not stand out.
Moshe defended the Jews to God, and argued that the Golden Calf was the act of rogue individuals, not the nation. Sin is an individual act – how could the nation be held accountable, regardless of how many had indeed sinned?
On his return, he saw to it that what he said was indeed true. The nation was whole and not fractured – he united them – וַיַּקְהֵל. This makes וַיַּקְהֵל unique as an opening.
The Nesivos Shalom proves this from what Moshe told them. He said of the laws that לַעֲשֹׂת אֹתָם – but the instructions for Shabbos that he mentions are to not light fire, and to not work. How is not doing something called לַעֲשֹׂת – to do?
Perhaps the instruction wasn’t discussing Shabbos at all; having conceded to Moshe’s argument, he received the instruction לַעֲשֹׂת אֹתָם – to make them, the Jews, into a united nation once again – וַיַּקְהֵל. Moshe was told to back up his claim!
This concept recurs over and over. When the spies were sent, the nation could not be absolved. They were sent in the capacity of the people’s representatives, and the generation died out. The Purim rescue occurred once the divided nation fought stood as one לְהִקָּהֵל וְלַעֲמֹד עַל-נַפְשָׁם. Korach’s error was not believing that the nation was more potent than the individual, claiming כולם קדושים.
Not to say that the laws Moshe spoke about were incidental to the purpose of gathering them. Far from it. They were chosen as both are incumbent on the nation, serving the same function, in contrast to more personal mitzvos,
The Midrash says that Hashem said to Shabbos that כנסת ישראל is its pre-ordained. כנסת ישראל is the Jewish national identity and consciousness, the supersoul of the nation. Shabbos observance is not down to the individual alone – it requires everyone’s input. Shabbos intrinsically unites Jews.
The Mishkan was selected for the discourse for the same reason. Everyone was required to make donation, buying a small stake in it. Covering the project costs with a few individual sponsors would not have served it’s purpose.
Both demonstrate the potency of a group over an individual. The parts in a machine are unremarkable – but together they achieve complex and sophisticated goals. Note how many mitzvos require groups to be adequately performed. The Nesivos Shalom says that we refer to Hashem as אבינו – our father – conceptually, obviously. If we identify with the nation, we can say אבינו.
We say in the Amida every day: ברכנו אבינו כולנו כאחד באור פניך – when everyone gets along, we can proudly say אבינו.