In this chapter, we conclude the listing of sacrifices required for public holidays.
I recommend reading my commentary on the prior chapter for more context, since these two chapters are inextricably linked.
As with the prior chapter, most of the sacrifices here have not been previously detailed. For instance, if you review the instructions for the Day of Atonement from Lev 16, the priest sacrifices something like two goats and two bulls. In this chapter, we can see that the community must offer seven male lambs, a bull, ram and male goat "besides the sin offering of atonement", which suggests that these are cumulative sacrifices on top of what has already been commanded.
Apart from the Feast of Booths, the sacrifices in this chapter and the larger festivals of the last chapter are all pretty consistent. It seems like most of them involve sacrificing approximately one or two bulls, one ram, seven male lambs and a male goat for a sin offering (in the case of the Passover, this was offered on each day of the seven-day festival). The eighth day of the Feast of Booths, which is a special day of assembly, returns to this formula. I don't particularly know why they use these numbers of animals. In particular, the variation between one and two bulls is suggestive that it involves a sacrifice on behalf of the priest and the people, like we saw in Lev 16, but that is somewhat speculative on my part. The offering of one male goat for a sin offering is also reminiscent of the Passover, as I discussed back in Num 21, and it foreshadows all of the same things: a solitary sin offering to bring reconciliation between the people and God. One could also argue it is intended to reference the unity of the nation.
Seven is the number of completion, so perhaps the seven male lambs are supposed to be a "fullness of sacrifices" or something roughly equivalent.
The only real exception to this pattern is the seven days of the Feast of Booths. The Feast of Booths was instituted back in Lev 23, which suggested that the Israelites should "present an offering by fire to the LORD" but without stating exactly what that offering should be. This chapter answers that question with a peculiar pattern. The Israelites are to offer two rams, 14 male lambs, a single male goat, and a number of bulls that starts at 13 and decreases by one each day. I was confused by this, so I loaded up my go-to commentary, Keil and Delitzsch (K-D). First, K-D compare it specifically to the Passover and Firstfruits because these three festivals were originally declared as a group in Ex 23:14-17, which suggests that the Day of Atonement and Feast of Trumpets should be dealt with separately.
Second, K-D note that the number of rams and lambs are doubled over the earlier festivals, and the number of bulls totals 70, which is 5 times greater than the earlier festivals. That is, since the Passover sacrifices 2 bulls a day over 7 days, it totals 14. K-D suggest that the Feast of Booths has these greater numbers because it was a celebratory festival at the end of the harvest year. I think this explanation is reasonable, since Lev 23:40 also notes that the Israelites are to "rejoice before the LORD your God for seven days" during the festival.
Third, K-D mention that the decreasing number of sacrifices on each day is possibly intended to leave seven bulls for sacrifice on the seventh day, since seven is a special number in the bible. This allows the total number of bulls to be seventy, while the number on the seventh day to be seven. I think this explanation is reasonable, but in my opinion it falls in the trap that numerology in general falls into: there are too many "good explanations".
By this, what I mean is that there are many numbers in the bible that have special meaning: 1, 3, 5, 7, 10, 12 are a few examples we have seen so far. For example, suppose the Feast of Booths required 10 bulls on each day. Then the total would still be seventy, and 10 is also a special number so in that case K-D and everyone else could come up with a "deep and meaningful" interpretation as usual. Or suppose the Feast of Booths required 12 bulls on 5 days, 3 bulls on the sixth day and 7 bulls on the seventh day. Then everyone could invent a creative and meaningful interpretation for that too.
I guess what I'm trying to say is that when it is possible to come up with a valid and meaningful interpretation for any arbitrary combination of numbers, then no interpretation can ever be particularly meaningful. It's like a Rorschach test where nearly any answer is valid, but that leaves me skeptical that even a "reasonable" interpretation can tell us more about the text than it does the interpreter. Does the seven bulls on the seventh day signify the completion of the festival, the "completeness" of the offering, the fullness of joy in their covenant with the LORD, etc? It could be none, it could be some, it could be all.
I think this kind of interpretational ambiguity is true of the entire bible, but nowhere is this truer than in numerology. I also think that in many places this ambiguity is intentional, a technique to force us to examine ourselves in addition to the text, and that the bible is meant to be a struggle and not a clear-cut answer. What makes this paradoxical is that the very source of ambiguity is numbers, which are in this case a symbol of concrete specificity. The numbers, like the dimensions of the tabernacle, are a rigid demand for conformity, that the Israelites must do things "exactly as the LORD commanded" (Ex 39:42 and 43). At the same time, in a search for meaning we look for patterns in the numbers, but since the numbers are never directly explained, it opens the door wide open to a shadowy world of subjective opinion and personal selectivity.
What makes this pursuit of meaning all the more entrancing is that with some numbers, like seven, the fact that it holds significance is obvious given how many times it's repeated. It is only the search for meaning that leads us down a rabbit hole of conjecture. The risk is to become like William Miller, wrongly predicting the return of Christ over and over, in the end resulting in the "Great Disappointment", and all based on his interpretation of numbers in the bible. Miller, like so many figures before and since, is a symbol of numerology gone awry, stepping beyond the search for meaning and into the realm of finding meaning that, as it turns out, did not actually exist. Miller's life, among others, is an example to me why we must tread softly where the bible is unclear. Even when we find meaning, I think it's important to not think of it as exclusive: often the bible teaches many different lessons from the same parable.
In conclusion, I think the search for meaning is significant and should not be abandoned just because it is difficult or perilous. To ignore the subtleties of the bible is just as great a fallacy as misinterpreting them. Instead, it is incumbent upon us to think clearly where the bible speaks clearly and to think carefully where the bible speaks unclearly. Second, and perhaps most importantly of all, we must interpret the bible with a prayerful heart and always seek the Lord for understanding, because the only way to genuinely understand the bible is when guided by the Holy Spirit who created it.