Breaking the Chains of Slavery
The reason that the Jews had to put blood on their doorposts was to rid them of the slave mentality. The purpose was not only to free them but to build them up to be free people.
We Are One Family
The Hagadah goes out if its way to show the unity of the Jewish people. That when some Jews are suffering then all Jews are suffering.
A Part But Apart of Society
We are taught that, while we should be involved in the society around us, that we should remember that we are also separate. To protect ourselves we should maintain our own customs and traditions.