The laws of sheviit and shemitta empower the dis-empowered.
The laws takes the source of fertility that makes for life and renewal and ties it together with the responsibility of the people to steward that source wherever they find it. The life source must be held as sacred, as the treaty with God, the Ruler, must be held sacred. That is why the laws of sheviit come at the end of the laws of miqdash, because they are the complements to those laws of the Sanctuary.
The ground of the laws of sheviit is the autonomy that God insists onto the people of Israel, to stand erect, unbowed by the slave-masters’ staffs. The deep teaching inscribed in the laws of sheviit and shemitta is that the repository of those values ought not to be situated in the government because it is in exactly these areas and regarding those values that the government’s leadership is particularly susceptible to decline.
The stewards for the life sources must be the people themselves. The laws of sheviit and shemitta say that when the power goes to the people, what the people need to do with that power is, in collaboration with God, to steward the environmental life sources.
The root of the treaty is with the people absent the leadership. God's treaty with the leadership is via the mishkan’s ministry while God's treaty with the people is a direct populist connection. That is why the laws of sheviit and shemitta are couched as cultural artifacts more than as religious laws or political mandates.