To the Wilderness

Passover is simply the occasion of Israel's redemption from the slavery of Egypt. The instructions are precise, succinct, and simple---all for the single purpose of "covering" the people of Israel during the judgments of Yahweh on Pharoah and the people of Egypt. That release from slavery has no connection to the "wilderness", and the people of Israel prior to their redemption have no clues as to what to expect in that "wilderness" experience.
"Let my people go, that they may hold a feast to me in the wilderness. (Exodus 5:1)
"Let my people go, that they may serve me in the wilderness. (Exodus 7:16, 8:1)
"Let my people go... repeated, repeated...
Freedom is the absolute pre-condition.
Feasting and serving are all contingent on being free to hear and obey Yahweh's commands, and until that deliverance from the bondage of slavery is accomplished the people of Israel can do nothing in Egypt.
The confrontation between Pharoah and Yahweh escalates as the judgments increase in intensity, and it is the approach of the final "judgment" that signals the unveiling of Moses final words to the People of Israel and Pharoah.
"We must go 3 days journey into the wilderness... (Exodus 8:27)
"...for we must hold a feast to Yahweh... (Exodus 10:9)
Still, there are no clues as to what the "wilderness" experience will be like.
In all cultures, a settled people of cities and farms wage a constant struggle with the unknown forces of the wilds. All frontier people hold the borders of "wildness" at bay until the settlers can occupy and tame. The people of Israel were in the settled and familiar territories of Egypt, under the sovereignty and protection of a powerful king. All this---the known and secure---was to be left for the unknown in the wilderness.
In this day, the command to come out of Egypt and be separate unto God must be finally transformed into a sense of urgency: the sovereign God of Israel, Yahweh, is demanding a response... We must go...
So in this day, the wilderness experience is not an option for the People of Israel. If in fact, there is any reality of the Passover experience in the life of an Israelite, the wilderness is the next step in the journey.
What is it that we must go to?
Three purposes are mentioned, though the details are not given until the wilderness journey is under way.
First: the People of Israel will be proven and tested in the wilderness. The "issues" of the people will be revealed, e.g. idolatry, and then dealt with by repentance or discipline or judgment...
Second: the People of Israel are to hold a feast in the wilderness.
Third: the People of Israel are to serve Yahweh in the wilderness.
These three purposes of Yahweh are inherent in His plan for the People of Israel and,
You and I must go into the wilderness for these three purposes of Yahweh.