When we usher in the Holiday of Passover with our Seder, we do so with “fours.” We drink four cups of wine, ask four questions and respond to four sons (children) etc. The number four is prominent because the Torah describes the Exodus from Egypt in four ways:
“I will take you out from under the burdens of Egypt, and I will save you from their labor, and I will redeem you with an outstretched arm and with great acts of judgment. I will take you as a people for Myself…” (Exodus 6:6-7)
These four stages of the Exodus include their freedom from torture, slavery, being prisoners in Egypt and their receiving the Torah which made the Exodus, with its experience of true freedom complete.  
Although these four expressions describe four aspects of the Exodus from Egypt, there is also an allusion to the future Redemption according to the Midrash that these four expressions and four cups of wine correspond to the redemption from the four exiles, the fourth being the one we are in right now.
However, the preponderance of the Seder is to reflect on the Exodus from Egypt.
The last days of the Festival of Passover, however, focuses primarily on the future Redemption, particularly the eighth day. This is reflected in the prophetic reading (Haftarah) which describes vividly the nature of Moshiach, his activities and his impact on the world.
Moreover, the Ba’al Shem Tov instituted a meal at the end of the eighth day and called it Moshiach’s Meal.” By attaching the theme of Moshiach to a meal the Ba’al Shem Tov made the concept of Moshiach more than just a theoretical idea but a physical and palpable reality that we can ingest and internalize.
The fifth Lubavitcher Rebbe, Rabbi Sholom Dovber Schneersohn of sainted memory, took the idea and reality of Moshiach to new heights and depths by introducing a new custom to take of drinking four cups of wine at the Moshiach Meal.
Based on the significance of the number four with respect to the Seder, we may conjecture that the four cups we drink at the end of Passover likewise reflects four aspects of the future Redemption.
The first aspect of the future Redemption is that we will no longer be subjected to any foreign government. We will have gained total independence. It goes without saying that in this stage there will be no more oppression and hatred directed against us by our enemies who to this day want us annihilated.
The second stage of the process of Redemption is that we will build the third Bais Hamikdash-Holy Temple in its proper site on the Temple Mount. The construction of the Bais Hamikdash will bring a revelation of G‑dliness in unprecedented measure.
The third stage of the Messianic Era will involve bringing all of the Jewish people from the entire world to the Land of Israel. Every Jew, even those who don’t know that they are Jewish, will discover their identities and return to their home.
The fourth stage of the Redemption will be the total transformation of the world in which all nations will coexist peacefully, and the entire world will bask in G‑d’s light.
To usher in these four phases of the Messianic Era, G‑d has chosen one human leader referred to as Moshiach-the Anointed one.
It stands to reason that Moshiach who ushers in the final Redemption also possesses four defining characteristics.
Indeed, in the Haftarah of the last day of Passover there are four verses that describe Moshiach. In the first verse it describes the spirit that will rest upon Moshiach and mentions the word spirit four times:
1: “And the spirit of G‑d shall rest upon him,
2: …a spirit of wisdom and understanding.
3: …a spirit of counsel and heroism,
4: …a spirit of knowledge and fear of G‑d.
The next few verses describes his activities and are likewise divided into four categories :
First: In detaining his activities the prophet Isaiah describes his ability to judge without using the senses of sight and hearing but with the sense of smell:
“And he shall be animated by the fear of G‑d, and neither with the sight of his eyes shall he judge, nor with the hearing of his ears shall he chastise.
Second, in the next verse the prophet continues to describe his judicial prowess in the way he judges the poor:
“And he shall judge the poor justly, and he shall chastise with equity the humble of the earth,”
Third, the prophet then describes how Moshiach will execute punishment on the evil:
“He will smite the earth with the rod of his mouth and with the breath of his lips he shall put the wicked to death.”
Fourth, the prophet sums up his approach to justice:
“Righteousness shall be the girdle of his loins, and faith the girdle of his loins.”
Effect on the World
The prophet Isaiah then details the effects Moshiach will have on the world. Here too he divides it into four categories:
“A wolf shall live with a lamb, and a leopard shall lie with a kid; and a calf and a lion cub and a fatling [shall lie] together, and a small child shall lead them. A cow and a bear shall graze together, their children shall lie; and a lion, like cattle, shall eat straw. An infant shall play over the hole of an old snake and over the eyeball of an adder, a weaned child shall stretch forth his hand.
“They shall neither harm nor destroy on all My holy mount, for the land shall be full of knowledge of the Lord as water covers the sea bed.”
“And it shall come to pass on that day, that the root of Jesse, which stands as a banner for peoples, to him shall the nations inquire, and his peace shall be [with] honor.”
Fourth: In the next few verses Isaiah describes the ingathering and unity of the Jewish people from all of the nations. This too will occur through he leadership of Moshiach.
“And it shall come to pass that on that day, the Lord shall continue to apply His hand a second time to acquire the rest of His people, that will remain from Assyria and from Egypt and from Pathros and from Cush and from Elam and from Sumeria and from Hamath and from the islands of the sea. And He shall raise a banner to the nations, and He shall gather the lost of Israel, and the scattered ones of Judah He shall gather from the four corners of the earth. And the envy of Ephraim shall cease, and the adversaries of Judah shall be cut off; Ephraim shall not envy Judah, nor shall Judah vex Ephraim,”
Let us hope, pray and anticipate Moshiach’s arrival and the Final Redemption so that we will celebrate Moshiach’s meal with him in the third Bais Hamikdash!