http://revach.net/article.php?id=3591

Section: Moadim   Category: Hagadah Shel Pesach
Avadim Hayinu: Chidushei HaRim - Do Yo Know What It Means To Be A Slave?
Avadim Hayinu, we were slaves to Paroh.  A slave has no personality and no self whatsoever.  He is property of his owner.  It is hard for us to grasp the concept of slavery today, but the Chidushei HaRim puts it in perspective in light of the following halacha.

The halacha is that if a non-Jew has children and then is Migayer, converts, he has fulfilled his mitzva of Pru U'Rivu with the children he had when he was not a jew.  However if an Eved has children and then he and his children are all freed to become full fledged Jews, he still has not fulfilled his obligation of Pru U'Rivu.

The reason, explains the Chidushei HaRim, is because the children he had as a slave are not associated with him at all.  He was simply a mechanism used by his owner to produce more slaves.  However an Eved is not considered a person with respect to even his own children.  Even a paternal bond doesn't exist.  His own children are ripped away and totally cut off.  He has absolutely nothing in this world.  Not one shred of self.  This is who we were (or weren't) in Mitzrayim!