From Aviva Zornberg: Although the Israelite wilderness experience begins in Exodus and concludes in Deuteronomy, the book of Numbers claims the interior of this world of wilderness as its peculiar territory. It evokes not only geographical terrain, but also an inner landscape, an "inscape," as it were - a world of imaginative being. Between Egypt and the Holy Land, the wilderness intervenes. As the Torah tells the story, this was meant to form a brief episode in the history of the Israelites, a passage between leaving Egypt - yetziat Mitzraim - and entering the Land. But the brief interlude suddenly and tragically swells to healthy proportions...What is the nature of this interim space, so terribly extended?
(2) And thou shalt remember all the way which the Eternal your God has led you these forty years in the wilderness, that God might afflict you, to test you, to know what was in your heart, whether you would keep God's commandments, or not. (3) And God afflicted you, and made you hunger, and fed you manna, which you did not know, neither did your ancestors know; that God might make you know that the human does not live by bread only, but by every thing that comes out out of the mouth of the Eternal does the human live. (4) Your garment did not wear out on you, neither did your foot swell, these forty years. (5) And you shalt know in your heart, that, as a parent corrects their child, so the Eternal your God corrects you.
From the Midrash Tanchuma
Rabbi Tanchuma interpreted: This is like a king whose son was sick so he took him to a distant place to heal him. On their way back. his father began to enumerate all the separate stages of the journey. He told him, Here was slept, here we caught cold, here you had a headache, etc.
Ramban on Bamidbar 1:1
Now this book is made up entirely of commandments that were relevant specifically to the Israelite's situation while they were traveling through the wilderness and of the miracles that were performed for them there, to recount all the marvelous deeds of the Lord who dealt so wondrously with them. It tells further how God began to put their enemies in their power, and commands how the land is to be apportioned among them. There are no commandments in the book that apply outside the wilderness situation except for a few of the commandments are sacrifices that were begun in Leviticus but not fully explained there; these are completed in Numbers.
Rabbi Shefa Gold, Torah Journeys, "Bamidbar"
The wilderness if the place of our journey. We wander for forty years. During this time the generation of slavery dies and a new generation emerges.
The harsh inner reality of the wilderness purifies whatever traces of enslavement we still carry. This wilderness is the midwife of our new life, after long and hard labor. The wilderness forces us to face the resistance, ambivalence and self-delusion that has kept us from whole-heartedly receiving our birthright: the promised flow of milk and honey that is given to us, and through us, with each moment of life. The wilderness will scare out all our old ghosts and send them forth from the shadows into the full light of awareness.
In the wilderness, we are stripped of disguises. Defenses fall away. Each part within us is forced to show its true face.
Aviva Zornberg, Bewilderments: Reflections on the Book of Numbers
The surface of the wilderness proves to hold vertical menace - Into this wilderness your carcasses shall fall!" the Torah intones repeatedly. This is not simply a walking surface for the traveling people, but a quicksand ready to consume human bodies.
It is an environment that is inimical to human life...The landscape does not yield to human demands: it frustrates the need for food and drink, but also the basic demand for direction, for markings to indicate a human mapping of blank space. No human steps have trod this sand, it stares back at the travel indifferently - pathless, bewildering to the human imagination. A kind of horror besets the mind. Already traumatized by their Egyptian past, the Israelites, one by one, must be swallowed into this senseless space.
...The experience of midbar, extended to the edges of life, suddenly becomes a total experience. These people will never know any other reality. But precisely there lies the central enigma of the narrative...Till the second census in chapter 26, the reader does not clearly understand that thirty-eight years have passed, with their full harvest of death. Only when the text clearly states that in this census there are no survivors from the earlier census at the beginning of the book (26:64), do we realize that, without our noticing, a generation has slipped into the sands.
The other "bewilderment" - also essential to this wilderness - is the lack of emunah, of faith, that continuously and repeatedly characterizes the people's utterances. Classic midrashic sources have suggested that midbar is closely associated with issues of dibbur, of language and utterance. Ein midair ela dibbur, declares one such source - "Wilderness is nothing but utterance" - cryptically playing with the roots for two terms. In which case, we can say that the Book of the Wilderness yields a human language of querulous skepticism. Cries and whispers and rages and laments fill the air, a cacophony that God describes as issuing from a lack of faith.