The word Va'eira means, "I revealed Myself," as in the verse, "I revealed Myself to Avraham, to Yitzchak, and to Ya'akov with the name EL SHADAI, but with My (true) name "ADONOY" ("Havayeh"), I did not become known to them" (6:3).
Why did the Torah stress the negative here - that God did not reveal Himself to the patriarchs with His True Name "Havayeh"? What lesson could we learn from this negative statement?
The redemption from Egypt was primarily a spiritual freedom which enabled a Jew to serve God without interference from gentile nations. Of course, the redemption from physical servitude is not insignificant, but in the ultimate scheme of things, the physical redemption occurred in order to make the spiritual redemption possible.
What, exactly, is a spiritual redemption?
The Alter Rebbe explains that this is the ability to serve God with total commitment, to the extent that a person has no private agenda at all (Torah Ohr. Va'eira 56a).
It is impossible for a person to achieve this level unassisted. So long as the person is working on his own, everything that he does is ultimately an extension of his "private agenda." Even if he will decide to become totally committed to God, it was his personal decision and thus, in the final analysis, his private agenda.
In order to become truly committed to God, one needs God's assistance. Thus, the Exodus from Egypt was to be a true spiritual redemption because it would involve Divine assistance from above.
This however begs the question: Surely the patriarchs were also privileged to receive Divine revelation, so why do we still need the spiritual redemption from Egypt?
Therefore, God told Moshe, "I revealed Myself to Avraham, to Yitzchak, and to Ya'akov with the name EL SHADAI, but with My (true) name "ADONOY" ("Havayeh"), I did not become known to them." I.e. it is only through a revelation of Havayeh - a name which' represents God as He transcends all limits - is it possible for a person to become truly committed to God, beyond the limits of his own personal agenda.
And so too it will be with the true and complete redemption, when we will be genuinely free to serve God, as "the earth with be filled with the knowledge of Havayeh like water covers the seabed" (Isaiah 11 :9).
(Based on Likutei Sivhos, vol. 31, pp. 23ff.)