The Yalkut says (Melachim 184) that although the Mishkan was completed on the twenty-fifth of Kisleiv, Hashem postponed its inauguration until the month in which Yitzchak Avinu was born.
The Zera Shimshon asks what significance there is in the fact that the Mishkan was completed on the twenty-fifth of Kisleiv. As well, why did Hashem want the inauguration to be specifically during the month in which Yitzchak Avinu was born?
The Zera Shimshon answers by quoting Rabbeinu Bechaya, who quotes a Midrash that says that the entire Mishkan mirrored the creation of Heaven and Earth. The Midrash goes on to show how this is. Hashem created luminaries to light up the sky; the Mishkan had the Menorah. Hashem created birds; the Mishkan had the Keruvim, and so on. (See the lengthy list in Rabbeinu Bechaya.)
Elsewhere, Rabbeinu Bechaya writes (Tetzaveh) that on the stones that were on the Choshen, there were a total of seventy-two letters corresponding to the seventy-two letters in the name of Hashem. The number seventy-two also appears in the creation of the world. This is because the world was only created during the daytime hours; six days times twelve hours is seventy-two. The number seventy-two in the creation of the world implies that the existence of this world is through the letters of Hashem’s name of seventy-two letters.
The Zera Shimshon then shows that the building of the Mishkan, which mirrored the creation of the world, was built in seventy-two days.
On Yom Kippur, Moshe Rabbeinu came down from Har Sinai and commanded the Jewish people about the building of the Mishkan. From Yom Kippur until the end of Tishrei there are twenty days. The month of Cheshvan is twenty-nine days. Add the twenty-five days until the twenty-fifth of Kisleiv, and the total is seventy-four days. However, two of these do not go into the count of building days since the passuk says that it took two days for all the necessary materials to be collected (Shemos 36:3, Shemos Rabba 41:2). And even though they did not build the Mishkan on Shabbos, the Zera Shimshon suggests that they learned all the relevant halachos of how the Mishkan had to be built so that they would be ready for the coming week’s building.
This, explains the Zera Shimshon, is the significance of the Mishkan being completed on the twenty-fifth of Kisleiv, seventy-two days of building, since it shows how the Mishkan corresponds to the world not only by what it holds inside it but even by the duration of time that it took to build it, which, in turn, hints to the seventy-two letters in Hashem’s name.
However, even though the Mishkan was completed on the twenty-fifth of Kisleiv, Hashem, in His mercy, only had it inaugurated during the month in which Yitzchak Avinu was born.
The Zera Shimshon explains this based on the Gemara (Shabbos 89b) that says how when the Jewish people’s sins reached an intolerable level, Hashem asked Avraham, Yitzchak, and Yaakov what He should do. Avraham and Yaakov said that the Jewish people were liable to death. Only Yitzchak stood up to advocate on behalf of the Jewish people.
Therefore, Hashem had the Mishkan inaugurated specifically in the month in which Yitzchak was born since, eventually, the Jews would sin, and due to Yitzchak Avinu’s argument, the Jews would not be destroyed; rather, Hashem would destroy the Mishkan (Beis Hamikdash) instead.
ZERA SHIMSHON
