What are the implications of the 'Mem' in "u'mi'Shamro es ha'Shevu'ah"?
Why did Hashem see fit to swear to the Avos ... ?
Ramban: To ensure that, even if we sin, our sins will not negate His promise to take us out of Egypt and give us Eretz Cana'an. 1
Ramban: Which explains why Hashem took us out of Egypt with a strong Hand (in order to keep His promise).
And what are the implications of the word "Vayifd'cha mi'Beis Avadim"?
Ramban: It implies that Hashem redeemed us by smiting the Egyptians instead of us.
Why does the Pasuk state that Yisrael were redeemed "from the house of slaves" and then add "from the hand of Par'oh, king of Egypt"?
Rashi (in Yisro): Refer to 20:2::1.