The sequence of narrative in Sefer Shemos seems quite puzzling, for the second aliyah of Parshas Va'era contains a partial genealogy list (Shemos 6:14-28), which commences with Reuven's family and concludes with that of Levi (Moshe and Aharon). Why is this ancestral information contained in our parshah? Although Rashi and other commentators explain the need for the Torah to trace the lineage of Moshe and Aharon, whose backgrounds were heretofore unfamiliar to us, and to start the presentation back with Shevet Reuven, why does this genaology list appear in Parshas Va'era, rather than in Parshas Shemos, where the Torah first introduced us to Moshe and Aharon? 

The answer to this question relates to very essence of Parshas Va'era. The parshah begins, "And I appeared to Avrohom, Yitzchak and Yaakov as K-l Sha-ai, but my Name Ad-ai I did not make known to them." (ibid. 6:3) Some commentators take this to mean that Hashem worked though nature and by private revelation when He dealt with B'nei Yisroel and with the rest of the world during the Patriarchal Period, whereas at the time of Moshe, Hashem communicated and interacted via open miracles and public display.

This change in Hashem's method of communication and revelation, which permeates and characterizes Parshas Va'era, starkly redefined His relationship with B'nei Yisroel, as they would now connect with Hashem "Panim el panim" (through Moshe) and experience Him in a wholly different way. (V. Targum Yonasan ben Uziel and Ramban ibid.) Thus, it was appropriate to again present Jewish lineage specifically in Parshas Va'era, as it is the parshah that marks the commencement of a new relationship between with Hashem and His people. It may also be for this reason that the genealogy presented in our parshah ends with Moshe and Aharon, for the new relationship with Hashem emerged and was revealed through them. It is as if the Torah now proceeds to enumerate our relationship with Hashem afresh, since the relationship underwent a dramatic change through the narratives of Moshe and Aharon in our parshah.

May it be Hashem's will that we again soon merit to experience His open revelation and complete deliverance.