In the aftermath of Nadab and Abihu’s innovating worship that ended up getting them fried to a crisp, the Lord speaks to Aaron directly saying, among other things, “You are to distinguish between the holy and the common, and between the unclean and the clean” (Lev 10:10 ESV). What follows in Leviticus 11-15 is instruction that would have been directly relevant for the priests’ objective of distinguishing between the unclean and the clean. These regulations regarding cleanness begin with distinguishing between clean and unclean food before turning to a number of other things that could make an Israelite unclean.
While the food laws certainly do not exhaust the investigation into distinctive living, they have been a source of much interest on account of how specific they seem to be. Now, at a basic level, there are few interpretive difficulties in understanding the point of Leviticus 11. Summarized in a word, the chapter teaches that eating whatever is detestable or unclean makes an individual detestable or unclean.
That, I hope, is simple enough, but there is a certain urge in us to want to uncover the logic of distinctive living, isn’t there? Why are certain animals unclean while others are clean? We want to account for this area of distinctive living, and I do think it is important to spend some time on it. This reflection will use the OT commentator Gordon Wenham’s four basic options for the logic behind it all before settling on a position.
First, there are those who would say that there is no logic, i.e. these regulations are arbitrary. While that might be a possibility for some, it is not for me on account of what arbitrary regulations communicate about the character of God. He is not capricious; he is a God of order. Nothing is arbitrary with God without giving up his unchanging and perfect character. Things might seem arbitrary, but then we are better off saying that these regulations are inscrutable (beyond us) rather than arbitrary.
Second, some would say that there is a religious logic to these regulations. That is to say, the unclean animals were those used in pagan religious rites, e.g. the pig, and so to make his people distinctive, God declared those animals unclean. While there might be some truth to this view, Wenham points out that many pagan religions also used clean animals for their religious rites. Thus, this logic doesn’t explain the data very well, and it also doesn’t help to explain many of the other regulations in chapters 12-15.
Third, some argue there is a hygienic logic. For example, consuming undercooked pork can cause trichinosis, which is a nasty disease caused by roundworm parasites (I’ll spare you the details). The logic of distinctive living, then, is that certain animals were avoided because they were more likely to cause disease. This logic, in my opinion, explains better the contents of Lev 12-15 than the prior options, but it still falls short. After all, trichinosis is easily prevented by thoroughly cooking your pork. At best, this might be an ancillary logic for some of the regulations, but it can’t make sense of everything.
Finally, some support a symbolic logic. This view argues that for each category of thing, e.g. land animals, birds, or sea creatures, the “normal” animals are clean while the deviants are unclean. In the case of land animals, whatever parts the hoof and is cloven-footed and chews the cud is the “normal” animal. The camel deviates from the norm in that it does not part the hoof (cf. v4), and all the animals with paws are also deviants and therefore unclean (cf. v27). In the case of swarming things, as in our text this morning, their method of movement is chaotic. That is their deviation from the norm of more orderly movement in a herd.
And the deviation of the swarming things helps us to appreciate that the symbolic significance is that some animals are better representatives of life and order while others more closely represent chaos and death. To use another example, birds of prey drink blood and scavengers eat the meat of dead or torn animals. They are, then, representatives of chaos and death and therefore unclean.
Ultimately, the point is that all of life, all of our choices and what happens to us, tends either towards life and order or chaos and death. Because God is life and the God of order, those things that tend toward life and order are clean, while those things that tend toward chaos and death make someone unclean.
 Gordon J. Wenham, The Book of Leviticus, NICOT (Grand Rapids: Eerdmans, 2009), 166–71.