I started Bernard Levinson's Deuteronomy and the Hermeneutics of Legal Innovation.
Levinson argues that Deuteronomy was associated with King Josiah of Judah's "centralization and purification of the cultus in 622 B.C.E., as narrated in 2 Kings 22-23" (9). Against scholars who maintain that Josiah was a fictional character invented in the exilic or post-exilic period---as a depiction of an idealistic king---Levinson contends that the embarrassing nature of the story in II Kings 22-23 shows that Josiah wasn't just made up. Levinson states:
"Throughout the Deuteronomistic History, the editor evaluates kings according to their conformity to a standard of legal righteousness. For that same editor suddenly to confess that the lawbook that served as the basis for his evaluations was in fact completely unknown and only belatedly discovered, and then only by chance, threatens to jeopardize the credibility of the entire enterprise...The anomaly is best explained under the premise that the narrative core of 2 Kings 22-23 is the work of a preexilic editor who sought to legitimate the introduction of a new set of laws and to sanction Josiah's cultic and political initiatives." (10)
For Levinson, had an exilic or post-exilic Deuteronomist simply made up the Josiah story out of whole-cloth, he wouldn't have presented the Law of Moses being discovered suddenly during the reign of Josiah, for that undercuts his claim that the previous kings of Judah were evaluated according to their obedience to that law. The Deuteronomist would not have made up that embarrassing detail, and so it must have been true.
Levinson's book is about how centralization impacted various issues. King Josiah banned sanctuaries throughout Judah and commanded worship to occur only at one central sanctuary, the one in Jerusalem, and Deuteronomy supported this agenda. But Deuteronomy had to interact with respected laws, the Covenant Code and other laws in what we know as the Pentateuch, in order to legitimize the agenda of centralization. These laws recognized and promoted the existence of local cults. Deuteronomy could not simply dismiss them, for they were respected, and so it went the route of rewriting and reinterpreting them. The altars of Exodus 20:24 were interpreted in Deuteronomy 12 as temporary---God permitted them before Israel had attained rest, but, once she gets rest from her enemies, she is to worship only at the place that God shall choose---the central sanctuary. The Covenant Code talked about judicial oaths at local sanctuaries, but, once those were abolished in the Deuteronomic reform, another judicial system would have to be set up, which Deuteronomy laid out. Prior to Deuteronomy, the Passover was a household apotropaic rite, and the Days of Unleavened Bread entailed a pilgrimage to the local cult. But Deuteronomy changed that, mandating that the Passover be slaughtered at the central sanctuary, not at home.
But, for Deuteronomy, centralization was not an absolute, perhaps because its authors realized that they could not totally dismantle localization, which was highly regarded by the people. Consequently, in Deuteronomy 12, the local slaughtering of meat is permitted. In Deuteronomy 16:18, there is a provision for local courts. According to Deuteronomy 16, the Passover had to be sacrificed at the central sanctuary, but the Days of Unleavened Bread were to be observed locally (in the Israelites' tents). On pages 49-50, Levinson states:
"In the face of the dismantling of the countryside cultus begun by Hezekiah and intensified by Josiah, it was crucial for the Deuteronomic authors to establish for the citizens of Judah that the loss of the local altars did not entail complete loss of local access to God or, more seriously, that God had abandoned the local sphere. They went out of their way to provide the local sphere with its own integrity. Yahweh continues to be active and to grant his blessing there."
When I was an evangelical, trying to find some practical application from Deuteronomy's insistence on a central sanctuary, the lesson I drew was that Christians should go to church and gather with other believers---recognizing that they are part of a larger body. They should not limit their worship to their one-on-one relationship with God, as present as God was in that. I had issues with this, however, because I tended to feel alone in church or fellowship settings. That's why I appreciate something that Levinson notes on page 91, whether or not it addresses my concern:
"The Israelite would originally have observed the festivals at the local sanctuary, which would have been part of his community and where he would have been known. Deuteronomy's command to undertake a pilgrimage to the central sanctuary to observe these festivals had to involve immense social displacement; not only would the new site have been unfamiliar, but the celebrant would himself be unknown in the Temple precincts. He would be surrounded by others alien to him, themselves feeling equally alien. The new command, therefore, would contribute to a breakdown of the local cultus and to a decrease in the dominance of the clan networks in conventional religious life. Deuteronomy replaces these with a corporate religion. The citizenry becomes constituted as a national religious polity as it now begins to celebrate the festivals at a single time, at a single place, and as a single body."
I'm reminded by this quote of how good it is to fit in somewhere, and yet we need to be reminded that there is a human race outside of our own cliques.