Parshas Shemos

The Parsha begins with the recounting of the twelve children of Yaakov. The Ohr Hachaim says that the Torah is praising them for going down and staying in Mitzrayim. They could have left - they had gone back to Eretz Yisroel to bury Yaakov - and yet they stayed in Mitzrayim, for that they deserve to be mentioned again.
Pesach night we begin the narrative of yetzias Mitzrayim saying that Esav settled in his land - Sayir, while Yakov and his sons went down to Mitzrayim. Who invited Esav to the Seder? Why do we mention him in our narrative of Mitzrayim?

The Medrash says that the land of C'naan was promised to Avrohom and Yitzchok. Of Yitzchok's two sons it remained unclear who should inherit the Eretz Yisroel - Yaakov or Esav. The catch was that Eretz Yisroel comes with a price. It is one of the things that can only be acquired with yisurim. Avrohom was told that his descendants would have to travel through 400 years of golus before they returned to Eretz Yisroel. The golus mitzrayim was the first step to us acquiring Eretz Yisroel. Esav knew all of this and he made a decision that he does not want the yisurim, nor Eretz Yisroel. It's not worth it. Esav took his family and nation and left Eretz Yisroel to settle in Sayir where he was happy and complete. Yaakov on the other hand was focused on the long term. He knew that there was a bumpy road ahead, but he also knew that it was rewarding. Instead of choosing to settle anywhere with his family and be content, he went down to Mitzrayim. He had a nation of Hashem to build. He had to start in golus.

We begin the Pesach seder with the realization that golus is not a punishment, but rather the growing pains to acquire Eretz Yisroel. These are the hardships that Esav chose to give up. So to the Torah begins the golus Mitzrayim giving a special mention to Yaakov and the shevatim for choosing the path of golus in order to inherit the land that was promised to Avrohom.