And I've also heard the cries of B'nei Yisroel, that the Egyptians made them work (Shmos 6:5).

This work refers to prayer. The harsh work of the Egyptians caused Bnei Yisroel to daven to Hashem. This is why they cried. They were embarrased that they didn't pray before trouble began.

--Arvei Nachal

And I will remove you from the suffering of Egypt...and I will take you to Me as a nation (Shmos 6:6-7).

Chazal deduced that the four cups of wine at the Seder correspond to the four expressions of redemption mentioned in these Pesukim.

Undisciplined freedom without adherence to Torah can be compared to drunkenness, where the person who indulges completely loses his senses. True freedom can come only through observance of Torah. Only after the fourth cup, which corresponds to I will take you to Me as a nation can one be considered free.

--D' var Eliyahu

For we wish to offer the abomination of the Egyptians to Hashem our Al-Mighty as a Korban (Shmos 8:22).

The Egyptians wished to present themselves as a compassionate and valiant people. It was for this reason that they took up the cause of kindness to lowly, downtrodden animals and they worshipped the lamb - a totally defenseless creature.

However, morals and ethics that are not of Divine origin have no stability and can be easily discarded based on the desires of society. Those very same "merciful" Egyptians - the defenders of the weak and helpless animals - became the most brutal and inhumane taskmasters to their fellow human beings.

In our own times we saw a striking resemblance between Germany and the Egyptians of old.

--Rav Yaakov Yoseif of Vilna

And Hashem did according to what Moshe had said and removed the mixed masses of animals from Paroh, from his servants, and from his nation (Shmos 8:27).

Rashi explains that unlike the frogs who died in Egypt, the mixed animals left Egypt when the plague ended so the Egyptians would not be able to benefit from their carcasses.

Why was it necessary for the frogs to die in Egypt? Why couldn't they leave just as the animals and locusts did?

Chazal tell us (Pesachim 53b) that when the plague of frogs was over, nearly all of the frogs died. The only ones that survived were those who were willing to sanctify Hashem's Name by entering the ovens of the Egyptians to fulfill His decree that they do so. Therefore, all of the other frogs died in Egypt in order to be contrasted with those frogs who performed a Kiddush Hashem and miraculously survived.

--K'li Yakar

Provide a wonder for yourselves (Shmos 7:9).

What is the difference between a 'wonder' and a 'sign'? A wonder is to demonstrate the greatness of the One who sent it and that He is worthy of being listened to. However, a sign is to testify regarding the messenger. Therefore, signs were performed by Moshe for Klal Yisroel. They had no doubts about the greatness of the sender and His abilities. They did, however, have concerns about the messenger (Moshe) and whether he was a true emissary of Hashem. Paroh, who was unsure of the greatness of the One sending the message and even denied His existence, I don't know who this Hashem is (Shmos 5:2), asked for a wonder to substantiate the claim of the greatness of the One who sent the message: something that would demonstrate that He was worthy of being heeded. It is entirely possible that the same act can affect one person as a sign and affect another as a wonder.

--Chizkuni

And they did not listen to Moshe because of shortness of breath and harsh labor (Shmos 6:9).

A person whose present condition is bitter and difficult does not have the mental capacity to hear about promises for a better future. Bnei Yisroel who were losing their stamina because of the harsh labor could not take in the words of Moshe at all. He was telling them how they were to be brought to a better land in the future. They had no concept of what would happen in their future. Their only priority was being released from the bondage that they were currently in. Therefore, Hashem said to Moshe that he should speak to them about the present only, To take Bnei Yisroel out of the land of Egypt (Shmos 6:13).

--Meshech Chochma