By Rabbi Joshua (patiently known as The Hoffer) Hoffman
In parshas Pekudei, we read that the mishkan was erected on the first day of the first month, or, in current parlance, the first of Nissan (Shemos 40:2). The Midrash Rabbah notes that even though the actual work of the mishkan was completed on the twenty-fifth of Kislev, God wanted to delay its erection until the birthday of Yitzchok. We need to understand why Yitzchok, more than the other patriarchs, had a special connection to the erection and dedication of the mishkan. Although we have, in the past, offered our own explanation for this connection, and also expanded upon an explanation offered by Rabbi Yosef Salant in his Be'er Yosef, I would like to mention another explanation offered by Rabbi Salant, and expand upon that as well.
Rabbi Salant writes that the reason the nation needed to wait after the completion of the mishkan before its dedication was because the mishkan served as an atonement for tor the sin of the calf, which came about when they thought Moshe was late in returning to them from Mt. Sinai, and had, in fact, died. They made the eigel in order for it to serve as a replacement for Moshe and lead them in the desert. Since the mishkan was to atone for the sin of the eigel, it was appropriate that part of this teshuvah process would include the need to exercise patience. What does this have to do with Yitzchak. Perhaps we can suggest that the defining character trait of Yitzchak, in kabbalah, is that of gevurah, or strength. My teacher, Rav Ahron Soloveichik, explained that strength exhibits itself in the ability to persevere in the face of adversities and failures. In parshas Toldos, the Torah tells us that the Plishtim filled up the wells that Avraham had dug, and Yitzchak continually re-dug them, until the Plishtim finally made a pact with him and ceased their destructive behavior. why were these wells so significant. Rabbeinu Bachya writes that Yitzchak would use these wells as a gathering point to teach people about God, just as his father had. despite all the attempts of the Plishtim to end this activity, Yitzchak persevered, and continued his father's work of teaching the world about God. Thus, it was Yitzchak who exemplified the trait of patience, and, therefore, the dedication of the mishkan was delayed until the month of Nissan, in which he was born, in order to train the nation in the exercise of this trait, thereby reinforcing thier repentance over the sin of the eigel.
Rav Moshe Tzvi Neriah, in his Ner LaMaor gives a different explanation fort he delay of the dedication of the mishkan until Nissan to correspond to the month of Yitzchak's birth. He writes that Yitzchak was the only person who was actually brought as a sacrifice to God, and the main purpose of the mishkan was to bring sacrifices, as the Rambam writes in the Laws of the Chosen House ( Beis HaBechirah). Actually, this was one of the reasons for connecting the mishkan to Yitzchak that Rabbi Salant offered. However, Rav Neriah adds an additional point in this regard. He writes that King Shlomo dedicated the Beis Hamikdash in the month of Tishrei, as soon as he had completed it. He did so in order for the dedication to correspond to the month during which Avraham was born, because Avraham was the one who brought Yitzchak as a sacrifice. Following Rabbi Salant's explanation of the need to wait in order to rectify the mistake which led to the sin of the eigel, we can understand why Yitzchak;s birth was commemorated with the dedication of the mishkan, while Avraham's birth was commemorated with the dedication of the Beis Hamikdash, when atonement for the eigel was not a factor.
Interestingly, Rav Zalman Sorotzkin, in his Oznayim LeTorah, notes that according to the Midrash Tanchumah in parshas Terumah the construction of the mishkan corresponded to the creation of the world. Although Rabbi Sorotzkin does not mention this, the Netziv, in his introduction to Shemos, writes that the book of Shemos is called by the author of Halachos Gedolos, 'Chumash Sheni,' or the second book, because it relates the spiritual completion of the universe. Following this comment of the Netziv, we can suggest that it is in this sense that the Tanchumah views the construction of the mishkan as corresponding to the creation of the heavens and the earth,since the mishkan infused the world with spiritual meaning. Rabbi Sorotzkin goes on to mention that there is a dispute in the Talmud regarding which month the world was created, in Tishrei or Nissan. Rabbeinu Tam, as cited in Tosafos to tractate Rosh Ha Shanah 27a explains that both opinions are true. God's plan to create the world was conceived in Tishrei, but He did not actually create the world until Nissan. So, too, says Rabbi Sorotzkin, the command to build the mishkan, which we have explained as constituting the spiritual completion of the world, was given in Tishrei, while the actual dedication, by which God's presence dwelled there on a permanent basis, came in Nissan. Perhaps we can add that, following the Rambam, the main purpose of the mishkan was to bring sacrifices to God, and, therefore, the concept behind the mishkan commemorates the birth of Avraham, who brought his son as a sacrifice to God, while the actual dedication of the mishkan, which, following Rabbi Salant's explanation, marked the completion of a stage in the nation's repentance for the sin of the eigel, took place in Nissan, to commemorate the birth of Yitzchak, who displayed the character trait of gevurah, which the nation lacked when it sinned. This element of repentance did not play a part in the building of the Beis Hamikdash, and, therefore, Shlomo dedicated it in Tishrei,the month he completed its construction, in commemoration of Avraham, whose spirit of sacrifice served as a model for those who would bring sacrifices to the Beis Hamikdash.
