The Tzemach Tzedek explained that the הא of הא לחמא עניא hints to the 5 types of grain that Matza (the bread of affliction) can be made from (wheat, barley, oats, spelt and rye). The word הא also means the letter Hey, which has the Gematria of 5.
The Frierdike Rebbe asked why we is the phrase בארעא דמצרים (in the land of Egypt) used to describe the place in which the Jews people ate the Matza. Wasn’t the Matzah eaten when they were leaving Egypt?
As well as eating Matza on the way out of Egypt, they also ate it during their slavery because due to the difficulties of slavery, they also did not have time to allow their dough to rise and they had to suffice with Matzah.
What is the connection to the second part of this passage where we invite people to eat with us at the Seder?
When the Jews were suffering as slaves in Egypt, it was not possible for them to invite guests to their meals. However, now that we are free from literal slavery, we are able to invite those who are in need as guests.
But even though we now enjoy greater freedom, we are still in Golus. For this we conclude that whilst this year we are here and we are slaves, next year we will be in the Land of Israel as truly free men.
~ First night Seder 5697
