The Israelites were commanded to have a Passover offering, a lamb, on that fateful night of liberation. Part of that command involves their wardrobe while eating the sacrifice. "Your loins shall be girded, your staves in hand and your shoes on your feet." Why specify what they Israelites were to wear?
My teacher, Rabbi Aaron Soloveichik, explained the singular historical fact that Jewish liberation never followed the pattern of many other liberation movements. The French Revolution, for example, was followed by a bloodbath of all those who were deemed enemies of the regime. The same happened in many other countries throughout history. When one group rebelled and took control, they usually became equally barbaric to those whom they had just defeated.
Not so the Jewish people. The Israelites were commanded to "love the Egyptian, for you were a stranger in his land." On the surface, one would think they should avenge all of the suffering they were put through! Certainly on a natural level, the Israelites should have desired to smash a few Egyptian faces. Nothing of the sort happened. How is that possible?
I believe there were two critical reasons for the Israelites to be enslaved in Egypt. They both relate to God's ultimate purpose for this world -- Tikkun, correcting. Fixing that which is broken takes precedence, in God's hierarchy of priorities, over rewarding that which is already fixed. As they say, a chain is only as strong as its weakest link. We are all part of the chain of humanity and human history, and as such, must make sure that the weakest links will still hold under pressure.
God's main tool for fixing the world is none other than the nation of Israel. I believe that's why our history has been what it's been. All of that oppression prepared us to go forth and fix the world. How so?
First of all, I believe we were enslaved in order to impress upon us the urgency of this mission. By experiencing suffering, by experiencing the worst injustice in this world, we become sensitized to the need to rid the world of such things. The people of Israel are always in the forefront of the fight for human rights and human welfare. We simply can't stand suffering, and dedicate ourselves towards its alleviation. Jews are always working to find the cure to the worst diseases, marching for the rights of the oppressed, contributing huge amounts of charity to help the poor, to strengthen education, to fix the world! This sensitivity is a direct outgrowth of our having "been there".
The nation that left Egypt marched forth with a sense of mission. We were headed for Mount Sinai, we were headed to receive God's law and finally understand how to make this world a beautiful place for all those who live in it. But still, why was that not also the case in the French Revolution? Why did those who rebelled for equality and brotherhood become oppressors who denied the equality and brotherhood of others?
This question brings me to the second reason for the Egyptian slavery. It was so that we do not become overly attached to this material world. It was so that we disdain physical things, and elevate spiritual purpose above all else. Egypt was a deeply materialistic society. It was hedonistic, licentious. Wealth and power were the highest attributes one could aspire to.
I believe that the terrible cruelty of the Egyptians made the Israelites reject them and their materialistic culture. One rabbi, a Holocaust survivor, once commented that he expected the Jewish people to forever reject all Western culture after the second world war. It should have been seen as being worthless, if such "high culture" could not prevent the countries that practiced it from becoming barbarians. It would've been expected for the Jews to throw out the German poetry and music that covered over the deep hatred that resided in their souls.
In truth, it is not the culture that was to blame. It was the elevation of that culture above all else. It was the stress put on the pleasures, physical or emotional, of this material world. The Israelites learned to put this world in its place. They learn to keep physical things subservient to spiritual things. When you are a slave, this physical world holds no attractions for you. A piece of bread is the most precious thing in the world to a man who is starving.
Rabbi Soloveichik stresses that there were two elements of liberation at the time of the exodus. First, there was the physical liberation from slavery. If that were all there was, though, we probably would have descended into vengeful behavior. After all, if this world is about feeling good, then we should want to punish those who made us feel bad. That, in and of itself, would probably feel good.
So there was a need for another element of liberation. Spiritual freedom. Spiritual freedom is only possible when we are not enslaved by our physical desires. That is the meaning of the wardrobe requirements of the liberation evening. Girding our loins means subjugating our physical drives to the spiritual goal of reaching Mount Sinai. We did not leave Egypt to feel good. We left Egypt in order to fix the world. That is the highest spiritual goal anyone could set.
In a sense, one could say that without the spiritual liberation, there really was no freedom. Yes, we would be losing the Egyptian taskmaster, but gaining the taskmaster of our own uncontrollable drives. Spiritual liberation, which is only possible through controlling our physical desires and de-emphasizing the material world, is what really set us free.
Thus, we gained two crucial tools for our job of fixing the world. We gained a sensitivity to all human suffering, and we gained an understanding that the spiritual, not the physical, is the key to true freedom. Without both of those elements together, you could not succeed in our mission. With them, we are and we will.