The Eighth Day - The Surprise of Revelation
This week's parasha describes one of the greatest climactic moments experienced in the history of Am Yisrael: the revelation of the Shekhina (Divine Presence) in the mishkan (tabernacle). The nation had exerted great efforts in order to build this "house" for God, and now the Shekhina was "entering" in order to "live" within it. Following the seven days of consecration described in last week's parasha, during which the kohanim were made ready for their tasks, we read in our parasha how God is revealed in fire before the eyes of the entire nation, "And all the nation saw and they shouted and they fell upon their faces" (9:24).
However, despite our anticipation of this auspicious day, there is something somewhat surprising in its very celebration: there is no mention of it in God's command to Moshe. Concerning the seven days of consecration, in contrast, Moshe is given explicit instructions (Shemot 29), and indeed the service conducted during these days, as we read last week, mirrors completely – almost word for word – that command. 
And yet here, at the conclusion of those seven days, God speaks to Moshe and suddenly commands him concerning an additional day - a day on which special sacrifices are to be offered by both the nation as a whole and by the kohanim. This extra day (i.e., the eighth day of consecration) is conspicuously absent from the command in Sefer Shemot, and it appears here for the first time. This eighth day is obviously to follow immediately after the preparations of the days preceding it, and therefore the text refers to it as "the eighth day" – the day following the seven preceding days. In addition to the literary introduction to the unit, the activities of the day likewise point to a strong connection with the seven days of consecration that preceded it. 
However, specifically in light of this strong connection, it is surprising that there is no hint of this day in God's original command to Moshe concerning the mishkan and its preparations. The command concerning the first seven days is so detailed and explicit that the absence of any mention of the eighth day is immediately noticeable and demands an explanation.
Why does the command in Sefer Shemot make no mention of the eighth day? Why does God hide the message of this day from Moshe and from the nation, revealing it only now?
The Ramban, in his commentary on the beginning of the parasha, addresses this problem and offers two possible answers:
"Behold, these sacrifices were not mentioned in the parasha of, 'This is the thing that you shall do for them to sanctify them to serve Me' (Shemot 29:1),
i. for there He commanded only concerning the days of consecration, and the days of consecration consisted of the seven days and their sacrifices, for now on the eighth day they themselves would offer the sacrifices…
ii. and perhaps in order to atone for the sin of the golden calf He added these sacrifices for them now, for when He commanded, 'This is the thing that you shall do for them to sanctify them,' they had not yet built the calf… and this calf on the eighth day was to atone for having made the calf."
The first possibility which the Ramban raises is related to the context in which the command in Sefer Shemot was given. There the focus was on preparing the kohanim for their service – how they were to be readied and sanctified, while on the eighth day this process of preparation was already completed and the kohanim were functioning in their role. This day was not part of the preparation of the kohanim for their tasks, and in this sense the eighth day falls outside of the context of the command in Sefer Shemot. We shall return to this solution below.
The Ramban's second possibility is that at the time when the original command was given to Moshe in Sefer Shemot (immediately after the giving of the Torah), this ceremony of the eighth day was not supposed to happen. All the special service of the sacrifices on this day were attributable the sin of the golden calf, which had occurred after the original command, and now they had to atone for this sin on a special day – the eighth day: "And this calf on the eighth day would atone for the sin of the calf." The Ramban here remains true to his exegetical understanding of Sefer Shemot, maintaining that the order of events described in this Sefer reflects the chronological order in which they actually took place, and that the sin of the golden calf came after the command to build the mishkan (part of which concerned the days of consecration). 
A brief survey of the sacrifices that Aharon is commanded to bring on the eighth day strengthens the Ramban's second view, since for the sin offering Aharon must take "a calf of the oxen (egel ben bakar)" (Vayikra 9:2). The term more usually found in the Torah is "par ben bakar." This departure from the regular terminology may be hinting that this sacrifice comes as a correction and atonement for the sin of the CALF, and therefore a "CALF of the oxen" must be brought.
At the same time, this interpretation seems somewhat strained. The purpose of bringing sacrifices on this day is directed towards the revelation of the Shekhina, which always requires special offerings. This is emphasized by Moshe when he presents the service of the day to Aharon and the nation:
"And he said to Aharon, Take for yourself a calf of the oxen as a sin offering and a ram for a burnt offering… And speak to Bnei Yisrael saying, Take a kid of the goats as a sin offering… FOR TODAY GOD WILL APPEAR TO YOU… And Moshe said, This is the thing that you shall do, AND THE GLORY OF GOD WILL APPEAR TO YOU." (Vayikra 9:2-6)
Can the Ramban really believe that this whole revelation of God to the nation was merely a result of the sin of the golden calf? Had it not been for that sin, would the nation not have been worthy of this revelation? Would the Shekhina then simply have entered the mishkan covertly, without any ceremony? It is possible, but seems unlikely.
I would like to adopt the first suggestion of the Ramban and to try to understand why it was so important that the original command concerning the building of the mishkan include only the preparation of the kohanim for their service (the seven days of consecration), while excluding any hint of the process involved in the revelation of the Shekhina within the mishkan (the eighth day). In other words, why could God command Moshe only concerning the preparation of the kohanim, but not concerning the actual revelation?
A discussion of this question requires that we examine the relationship in other contexts between a seven-day period and the "eighth day" that follows. Let us review the most outstanding instances as they occur in the continuation of Sefer Vayikra:
1. 'ZAV' AND 'ZAVA' (people who experience a running issue from the flesh): The process of the purification of a zav and a zava basically consists of two parts: first – seven days during which the subject must count his purity (i.e., "seven clean days"). On the day after these seven days (called by the Torah "the eighth day" - Vayikra 15:14, 15:29), the 'zav' or 'zava' must bring offerings to the mishkan.
2. 'METZORA' (loosely translated as 'leper'): The metzora's process of purification consists basically of three parts. The two latter parts mirror the purification of the zav and zava – firstly, he must sit outside of his dwelling for seven days (Vayikra 14:8), and following this, "on the eighth day" (14:10), he must bring sacrifices to the mishkan for atonement.
3. THE AGE OF AN ACCEPTABLE SACRIFICE: An animal that has just been born must not be brought as a sacrifice; rather, "When a young bull or a sheep or a goat is born, it shall be with its mother for seven days," and only "from the eighth day onwards it shall be acceptable as an offering by fire to God" (Vayikra 22:27).
4. THE OMER: It may be tseven countings of seven days are to be regarded as a parallel on the same model as a single counting of seven days. In other words, perhaps the counting of the Omer should be regarded as basically a counting of seven days, but one which is executed seven times (7x7), following which the "eighth day" arrives – in this case the fiftieth day (Shavu'ot). Attention should be paid to the wording of the text: "Until the day after the seventh Shabbat (week) you shall count fifty days, and you shall offer a new meal offering to God" (Vayikra 23:16). The seven Shemitta cycles (7x7) followed by the fiftieth year (Yovel) should be regarded in a similar way.
5. SUKKOT: The seven days of Sukkot and the "eighth day" which follows them are also perhaps connected with this same basic model.
All of the above examples demonstrate that there is a closed system of seven days that is nothing more than a preparation for the eighth day that follows them. This eighth day does not have an independent status; it is simply "the day after" – but it is in fact the whole purpose of the seven preceding days. The seven days are a necessary preparation for the stage that follows them – on the eighth day. But the examples brought above show something more than this: the purpose of the preparations during the seven days is always a renewed entry into the mishkan and a renewed appearance before God.
This idea is highlighted in the process of the purification of those who are ritually impure: the zav and zava count the days of their impurity, the purpose of this counting being to re-enter the mishkan - a renewed appearance before God. On the eighth day they may once again approach the holy precinct: "And he shall come before God to the door of the Ohel Mo'ed" (Vayikra 15:14). From that day onwards they are entitled to bring their offerings whenever they wish to. Similarly, the law of the metzora emphasizes his renewed appearance before God on the eighth day: "And the kohen who purifies shall present the person to be purified and those things (i.e., the offerings of the eighth day) before God at the door of the Ohel Mo'ed" (Vayikra 14:11).
In a different but similar sense, an animal is acceptable as a sacrifice from the eighth day ONWARDS – in other words, once the seven-day unit has been completed, it is acceptable as a sacrifice and may be brought into the mishkan and offered upon the altar.
It would seem that the counting of the Omer also expresses the same idea: that we must engage in communal preparation for the fiftieth day, when the new meal offering is brought to the mishkan. The entry to the mishkan of the meal offering - brought from the new produce - is dependent on a prior communal counting of seven weeks.
In any event, the seven days of consecration are to be viewed as advance preparation for the purpose which stands at the foundation of these days – the eighth day, on which the Shekhina enters the mishkan for the first time, sanctifying it by the very revelation before the entire nation. During the course of the seven days the kohanim are sanctified and prepared for their duties; at the same time the altar is also sanctified during these days, and after they are all ready for their appointed tasks, the Shekhina is able to enter the edifice.
In light of the above, I believe that we should regard the question that we originally posed as part of the actual message of these days. What I mean here is that we should see the lack of any mention of the eighth day in the original command to Moshe as being meant to show that there is no certainty that that day will in fact occur! Am Yisrael may perform everything as they are commanded to – to exert themselves in the construction of the mishkan, to sanctify the vessels within it and to prepare the kohanim who will serve - but the revelation of God and His entry into the mishkan will remain uncertain until the moment of His decision.
The command concerning the eighth day cannot be given before the mishkan is built and before the seven days of consecration. Such a command would turn the appearance of the Shekhina in the mishkan into the result of a magical, almost deterministic process, and this is not the case. The appearance of the Shekhina in the mishkan depends on God's free will, and only if He finds the nation worthy will He dwell among them. Of course the purpose of constructing the mishkan and of the seven days of consecration is the eighth day – God's revelation in the mishkan – but the day of entry of the Shekhina cannot itself be commanded. This day remains elusive until God wills to enter and dwell within the mishkan built by His mortal children.
A substantial part of God's revelation is its element of surprise. A person may prepare himself, aspire to such an event and prepare the ground for its realization, but the revelation itself will always remain independent of him. It bursts suddenly into the world, and man, with all his psychological preparation, will always be thrilled and elated: "And all the nation saw, and they shouted and fell upon their faces" (9:24).
(Translated by Kaeren Fish)
 The single exception concerns the time of the sprinkling of the blood upon the kohanim, but a discussion of that issue lies beyond the scope of this shiur.
 Suffice it to note that, for example, on the eighth day – as on the seven preceding days – the sin offering (chatat) is burned outside of the camp, although the blood of the sacrifice is placed upon the outer altar; in other words, this is not an "internal chatat" offering. This is an unusual phenomenon, for, generally speaking, the kohanim eat of the flesh of the chatat whose blood is sprinkled upon the outer altar (as we read in chapter 4). This unusual procedure, which takes place during the seven days of consecration of the mishkan and which also occurs on the eighth day, creates a continuity of special days during which the outer altar is given special treatment. We shall not dwell here on the actual burning of the chatat sacrifice outside of the camp; the point here is to note the strong connection between the two units – the first seven days, and the eighth day that follows them.
 Rashi, by contrast, maintains that the command to build the mishkan was given to Moshe after the sin of the golden calf, and that "the Torah does not follow chronological order."
 The crux of Shavu'ot – the giving of the Torah (which is not mentioned explicitly in the text) - is also connected thematically to this idea, since (in the words of the Ramban at the beginning of Sefer Shemot) the mishkan represents, in many ways, a continuation of 'ma'amad Har Sinai.' God, after descending to Har Sinai, did not return to the heavens, as it were, but rather entered the mishkan to dwell among Bnei Yisrael. Thus, the preparation for ma'amad Har Sinai parallels the preparation for the eighth day, in which God is revealed in the mishkan.