Another explanation is that we are to remember that we were slaves in Egypt and therefore must care for other people, especially those on the margins of society. The commandment to remember that we were strangers or slaves in Egypt is the most repeated commandment in the Torah. We are to act on that awareness at all times, not just during Passover.

      I want to suggest a third explanation that combines elements of the first two. It is not just slavery that we are to remember but redemption as well. Redemption is the real foundation for Judaism. When Abraham first makes the journey to Canaan, he is not ready to inherit the Promised Land. He is still only a family, not a people. In Egypt, we will become the people of Israel. We will see how easy it is to mistreat other people who are different from ourselves. It was simple for Pharaoh to convince the Egyptians to persecute, enslave, even murder their neighbors who they perceived as different. 

      The prelude to having your own country is to see how easy it is to discriminate against others. What will happen in Canaan to the indigenous people who are already living there? Should we pretend they don’t exist, like the new Pharaoh who forgot about Joseph? When we establish our country, how will we treat the new immigrants who will inevitably come? Will we remember that Abraham was an immigrant? Or will we echo Pharaoh’s words to the Egyptians: we need to persecute the swarming Israelite newcomers lest they replace us?

      When the Israelites left Egypt as a free people, they took with them the bones of Joseph. They did not forget Joseph. They carried with them their past and the lessons of Egypt. They also put on their shoulders matzah, to acknowledge that redemption is possible and that it is to be shared not hoarded. To walk in God’s ways is to spread freedom wherever we go.