The redemption of the Jewish nation from Egypt is the bedrock of the Jewish faith. The more visible part of the process includes the incredible miracles associated with the redemption; miracles such as the ten plagues and the splitting of the sea, that would never be repeated again in history. These miracles serve as a foundation for the core beliefs of the Jewish people: i.e Divine providence and Hashem's omnipotence. We therefore understand why these are a core part of the geulah process.
But the passuk describing the great and magnificent event of the Jewish people being taken out of Egypt adds another crucial point and states (Devarim 4:34), "Has G-d ever taken out a nation from within a nation through such great and astounding miracles...?" The phrase "a nation from within a nation" is a bit redundant. Obviously, redemption means to be freed from your enslaver, exploiter, etc. Chazal (Midrash Tehillim 107) give us two different analogies illuminating the meaning of "a nation within a nation": 1) R' Avuha says, it is comparable to a calf in the mother's womb, that at the time of birth needs to be eased out. 2) R' Ibo says, it is like a goldsmith extracting the gold from the ore. Both of these descriptions, however, are not really conveying the extraordinary difficulty of the event. There is no mention of how strong and tough the Egyptians were; nor how great a miracle it was. Just what are we adding to the description of the great miracles and wonders when we say, "like a calf from the mother's womb" and "like gold from its ore"?
The Maharal (in Gevuros Hashem) describes another dimension of the geulas Mitzraim: when we think of the miracles associated with taking the Jewish people out of Egypt, we tend to focus on the difficulty of combating the Egyptians, the most powerful nation at that time. But there is a much deeper difficulty in the redemption of the Jewish people from Egypt. The Jewish people themselves had been subjugated and acculturated into the Egyptian society for two centuries. Two hundred years of being buried deep in Egyptian society had almost entirely erased any trace of a sense of being Jewish. As the Rambam (Hilchos Avoda Zara 1:3) says, "the roots planted by the Avraham had just about been uprooted". In order to have the process of redemption, there needed first to be an awakening of this sense of being Jewish.
"A nation within a nation" describes that conflicting duality of identity. When a fetus is in its mother's womb, it is in some sense part and parcel of the mother, while in some sense it is its own being. Its identity is a tug of war between these two identities. Therefore, Hashem had to take out "a nation from a nation".
This perspective helps us understand the two examples cited by the midrash - the fetus from the cow, and the gold from the ore. The gold locked into the ore is much harder to extract than the fetus from the mother. It requires breaking the ore to pieces and applying a tremendous amount of heat. But the gold is of an entirely different nature than the stone that it is bonded to, no matter how difficult to process it is to separate it out. On the other hand, the fetus in the mother's womb it is easier to separate out, but it is inherently of the same flesh and blood as is the mother. It takes a tremendous amount of self-awareness to perceive oneself as being an independent entity despite the fact that the fetus is identical in substance to the mother.
One can now understand the hardship of the Jews' suffering in Egypt, and the process of enslavement and labor imposed on them, as leading to this goal. They needed to come to the painful awareness that they are not, and never will be, Egyptian. The real Egyptians see them as an alien insertion, and even after years of being such productive members of society they were being rejected. In the rejection of the Egyptians, the Jewish people found their own identity. It is almost identical to the birthing process where it is the powerful contraction of the mother that pushes the fetus out, many times unwillingly. Only then can the calf stand on its own feet and begin to realize who it is and what it is.
This is a timeless understanding of the relationship of the Jewish people with the nations that they find refuge in, and in whose societies they become enmeshed. At almost every junction we began to feel at home, and slowly became or tried to become absorbed in the host society. Whether it was Spain or Russia or Germany or any other country that we were hosted by, we slowly began to become integrated, or at least wanted to become integrated. And then inevitably, Hakadosh Boruch Hu arouses powerful forces in our host country, rejecting us.
These rejections are harsh and traumatic, beginning with the psychological aspect of being considered the outsider, to the horrendous sufferings visited upon us by many of these host countries. And it almost always ended in expulsion. As painful as they are they are, these are the forces that shape us as a nation.
Wandering for millennia in other countries, and being as talented and as easily adapting as we are, the danger of becoming absorbed in another culture is great. And once absorbed, we would chas v'shalom lose our own identity, eternally. But Hashem has promised that we will never disappear. Therefore, in golus after golus, Hashem begins a process of "goy mikerev goy", extracting "a nation from within a nation". The first step of geulah is to sense that indeed we are a nation apart from our host. Sometimes we are intensely cognizant of it, and sometimes Hashem needs to employ our host remind us that this is so.
Once we come out and recognize ourselves as being unique and an independent entity, the geulah has begun!