This is something I read from:
Weekly Parasha Insights by Rabbi Eli Mansour
Description: Parashat VaEra: Making Exile Intolerable
In the beginning of Parashat Vaera, G-d speaks to Moshe and commands him to convey to Beneh Yisrael His promises of redemption. The first promise is “Ve’hoseti Etchem Mi’tahat Siblot Misrayim,” which is commonly translated as, “I shall take you from under the suffering of Egypt.”
The word “Siblot,” which is generally understood here to mean “suffering,” also has another meaning – “tolerance.” One Rabbi thus explained that G-d here promises to remove Beneh Yisrael from their “tolerance,” from their acceptance of their situation. It is natural after many years of suffering adverse conditions to accept the situation and no longer feel a need to change it. That this occurred to Beneh Yisrael is evidenced by the fact that later, during the nation’s travels in the desert, there were times when they cried to Moshe and nostalgically recalled their experiences in Egypt. As miserable as their conditions were, with time they resigned themselves to the situation and accepted it the way it was, without seeking to change it. This is a very common and natural tendency, but it needed to be reversed before Beneh Yisrael could be freed from Egypt. In order for Beneh Yisrael to be worthy of redemption, they needed to find their situation intolerable. And thus the first step in the process of Yesi’at Misrayim was the people’s release from “Siblot Misrayim” – from their ability to tolerate their conditions of bondage. The process of redemption could not begin unless the people wanted it. G-d therefore had to help extricate them from their acceptance of slavery as a tolerable condition before the Exodus could unfold.
http://www.dailyhalacha.com/m/parasha.aspx?id=478