After the four expressions of Redemption, why does Hashem add, "and I shall be for you as Elokim"?
Maharal #1 (End of Gevuros Hashem, "Hilchos Pesach bi'Ketzarah," p. 331): After the four expressions of Redemption, Hashem adds the promise "v'Hayisi" - that He will support Bnei Yisrael with all their needs. Hashem, in His role as Sustainer, is expressed by the Name 'Elokim,' as in the verse, "Elokim, Who has shepherded me from my outset..." (Bereishis 48:15). 1
Maharal #2 (Nesivos Olam, Nesiv ha'Avodah Ch. 7, p. 96): In Ma'ariv, after the blessing for the Redemption "Ga'al Yisrael," comes a blessing requesting protection - "... Shomer Amo Yisrael la'Ad." After Hashem redeems us from the domain of other nations, He "spreads His Sukah of peace" over us, so that no one may harm us. This is the idea in our verse as well; 'After redeeming you, I shall be your G-d to protect you always.'
Maharal: A such, it is an extension of the four expressions of redemption - ... 4) "I shall take you unto Me as a nation; 5) and I shall be for you a Sustainer." Maharal (Gevuros Hashem Ch. 65, p. 303) - According to the sources, one who wishes to drink a fifth cup, recites the Hallel ha'Gadol (Tehilim 136) over it. This Perek includes praise of Hashem for sustaining the world - "He gives bread to all flesh - for His kindness is forever!" (ibid. v. 25). (See Maharal further as to why this cup is not obligatory. Also refer to 6:6:3:8*.)
What was Hashem telling Moshe when He said, "vi'Yeda'tem Ki Ani Hashem .... "?
Ramban #1 (citing the Ibn Ezra): Bnei Yisrael should know that Hashem is taking them out of Egypt prematurely - even though according to the stars, they ought to have remained in Galus for many more years.
Ramban #2: When Hashem would now take them out of Galus with an outstretched Arm for all the nations to see, they would know that it was Hashem performing open wonders, that He is their G-d and that He is doing all this on their behalf, because they are the portion that He has chosen for Himself.
Seforno: Hashem was instructing Yisrael that, when they witness all the miracles that He is about to perform, they should realize 1 that it is Havayah who is rescuing them from the burdens of Egypt.
Seforno: "Vi'Yeda'tem " does not mean 'You will know,' but rather "you shall know." It is incumbent upon them to take note of the miracles and to realize who is performing them (in the same vein as the same word in Parshas Ekev, Devarim 11:2.
What are the connotations of "ha'Motzi Eschem... "?
