This week's Parsha begins with Hashem telling Moshe about the promises He made to the Avos (שמות ו':ג'-ד'), especially the promise He made to the Avos that Eretz Yisrael will belong to them. As noted by Rashi (שם פסוק ג' בד"ה ושמי), the Avos did not witness the fulfillment of the promise made to them, yet they did not grumble about it. Although Avraham Avinu knew that Eretz Yisrael would eventually be his, he did not become agitated when he had to buy a plot of his own land to bury his wife (בראשית פרק כ"ג). Yitzchak did not complain when the shepherds of Gerar disputed his rights to the well (שם כ"ו:ט"ו-כ'). When Yaakov wanted to erect his tent upon returning to Eretz Yisrael, he had to buy a field for one hundred coins (שם ל"ג:י"ט), but he had no second thoughts and did not question Hashem.
The trait of loyalty to Hashem that we see in the Avos is carried through to Bnai Yisrael in the land of Egypt. When the work got very hard Bnai Yisrael cried out to Hashem for help (שמות ב':כ"ג). When Hashem heard their cries, He decided that the loyalty displayed by Bnai Yisrael is like the loyalty that the Avos showed to Hashem, and He decided that He would then redeem Bnai Yisrael and fulfill the promise that He had made to the Avos.
A question that bothers many of the commentators is the question as to why the Torah in our Parsha (שם ו':ו'-ז') uses four different expressions of redemption as opposed to one, since usually the Torah is as concise as can be. Obviously, if these expressions are in the Torah, each one is here to teach us something. Some explain that the redemption did not happen overnight, it was rather a gradual process. Each one of the expressions thus represents a different stage of the redemption. The first indicates that the hard work actually ended six months before they left Egypt. The second signifies that by the month of Nissan, they were no longer under Egyptian authority. The third represents the splitting of the sea and the drowning of the Egyptians, and finally, the fourth hints at Bnai Yisrael becoming Hashem's nation through the giving of the Torah.
We too are in Golus today and await our own redemption. Just as the Avos and Bnai Yisrael were loyal to Hashem before the promise to them became reality, we also should be loyal to Hashem in order for the Geulah which we await to become a reality. We must understand that just as the redemption didn't happen overnight for the Jews in Egypt, it will be a gradual process for us as well.