There have been many suggestions as to Judaism's most fundamental concept.  Here's my candidate:  In each and every generation, each of us must see ourselves as if we left Mitzrayim.

Rav Kook says each of us took something from that experience that the world needs before it can be fully redeemed.  Our father Abraham knew well how to argue with God, but he didn't argue when told his descendants would be slaves for 400 years.  We needed to live through the affliction, and come out onh the other side, in order to empower others to do the same.  We remind ourselves, each year, of our history and our responsibility. 

We are commanded not to oppress the alien in our midst.  That alone requires much intention.  But, like God and our neighbor, the Torah commands we love the alien, the stranger, the undocumented farmworker or nanny.  Why?  Because we were aliens in the Land of Mitzrayim.  The Torah is explicit:  our experience in Egypt demand us to empathize with those who are in similar states of vulnerability.  That's our contribution to redemption.

haggadah Section: Koreich
Source: Rav Shai Cherry