Likutei Moharan 70:3/ליקוטי מוהר"ן ע׳:ג׳

13. This is [the explanation of the opening verse]: “On the eighth day Moshe summoned Aharon, his sons, and the elders of Israel.” When the tzaddik has to summon the nation’s leaders, he does so by erecting the Tabernacle, <from which all> glory comes. This summons them, because they all come in order to receive glory <and authority> from him. This is: “On the eighth day” Moshe erected the Tabernacle, and through this “Moshe summoned Aharon, his sons, and the elders of Israel”—all the leaders of the nation, from small to great. By erecting the Tabernacle he summoned all the nation’s leaders, who correspond to “Aharon, his sons, [and the elders of Israel].”

2And this is the meaning of what our Sages, of blessed memory, taught: Nissan is the New Year for kings (Rosh HaShanah 2a). It was then that the Tabernacle—the source of the glory of kings, and of all officials and leaders—was erected. This is why the Tabernacle was erected specifically on the New Moon—for this is the concept of ROSh ChoDeSh (the New Moon), from which all the ROShim (leaders) nitChaDShim (are renewed)—and especially the New Moon of Nissan, the New Year for kings.