For the rulers and authorities in heaven to learn, through the existence of the Messianic Community, how many-sided God's wisdom is.
Moses continues his exhortation to the children of the Children of Israel who left Egypt. He outlines God's credentials with, "For ask now of the days that are past … whether such a great thing as this has ever happened or was ever heard of (Deuteronomy 4:32)". Then he goes on with expounding on the events surrounding the Exodus of their fathers.
The Exodus is God's testimony to mankind of His superiority over all the gods and powers in heaven and on earth. It is the testament of His ability to fulfill the promises He made to Abraham, and that in spite of any unforeseen developments in the dynamics of the History of His people. If God says so, He is able to fetch His people from abject slavery in the lowest cultural strata of Egyptian societal gutters, and make them a free sovereign people which eventually became the Light of God to the nations around them. That's what Moses wanted the children of the Children of Israel to understand as they readied to conquer the Land before them.
As Paul teaches the Gentile believers of Ephesus, he reflects the Exodus events that showed God's superiority over the gods of Egypt into his own time and work as an emissary to the Gentiles. He says that though it was not known by the ancients, through the Messianic Congregations the manifold wisdom of God might now be made known to the rulers and authorities in the heavenly places. This was according to the eternal purpose that he has realized in Messiah Yeshua our Lord (Ephesians 3:5-6; 10-11).
In other words, our fathers didn't know it, but as the gods of Egypt learned of the superiority of God through the Exodus of the children of Israel, now the gods of Greece and Rome (which are really the same) were going to learn the same lesson through the exodus of their children into the Messianic Congregation of Yeshua the Messiah. And that my friend is God's universal plan, not only to redeem His children from slavery to the world, but to demonstrate to them as well as to all the powers in heaven and on earth His ability to deliver them. We are like the cherished prize of two contenders, only the game is thrown, as we already know the Winner!
In the same manner as the God of Israel delivered the Children of Jacob from slavery and showed the rulers and gods of Egypt 'a thing or two', He now delivers His children from the other nations and shows their rulers and gods 'a thing or two'. As the children of the Children of Israel were to look back at what happened to their fathers in order to mature their faith, the children of Israel of today, along with those of the nations, are also to look back to these events as a testimony of God's power to save us all from this idolatrous and wicked world, thus the importance of celebrating the Passover Seder.
May we all learn in this day and age the many lessons of trust, faith, and obedience that can only be learned as we sit at the feet of Adonai in the 'wilderness' times of our lives, as we hear hear from Him at His Holy Mountain. May we also learn to also fear God, the Creator, the Ruler of the universe, the Deliverer of His people, and fear Him only!