The relevant quote I found was this:
The holy God comes to dwell among Israel and opens His house to His people. They aren't ready to come all the way in, so He institutes procedures and protocols to limit and control their approach. They can only come near if they are clean, and only through animal mediators. As in the garden, God has rich gifts to offer, but He will only give them when Israel is prepared to receive them. A good gift given or taken prematurely is a pharmakon, poison.The point was that Leviticus represents, in retrospect, something of veneration. The Torah was a law given to govern Israel, but now it ceases to have any power. However, it still remains as a source of life even if its prescriptive ability has been canceled. This reminded me of a quote from Agamben's State of Exception, which is, in a way, a summary of Agamben's goal in his work:
What opens a passage towards justice is not the erasure of law, but its deactivation and inactivity- that is another use of the law [...] What is found after the law is not a more proper and original use value that precedes the law, but a new use that is born only after it. And use, which has been contaminated by law, must also be freed from its own value. This liberation is the task of study, or of play (64).Agamben's point is that law can only bring life in its ceasing to be enforced, and instead operating as a dead letter which can be drawn upon to build life. Hence, the new use of the law is study and play. In this Agamben, following a story by Kafka, reflects upon the revolutionary potency in the impotency of the Torah, which rabbis pour over and study, even as it has ceased to function.
In some ways, this draws upon the Apostolic use of the Old Testament in their own argumentation (Agamben is an odd student of St. Paul in this regard). It's interesting to see how Paul uses a Torah commandment about oxen eating the grain they tread as a means to model the idea of paying elders of their community.
I think there's something to this, especially in how Christians are to conceive of ethics. However, this seems to be something of what Leithart sees in Leviticus. God has deactivated the Torah in the Messiah. We are no longer beholden to stone tablets, but a heart made of flesh. Perhaps, this is the potential for the Law of Liberty that St. James references. We study Leviticus as Christians because we see in it the power of life, where the death-dealing powers of the Law have been canceled. In this, Leviticus makes known the life of the world.