And Hahsem spoke unto moshe, saying "I am Hashem. I appeared to Avraham, to Yitzchak, and to Yaakov as El Shaddai, but with my name Hashem I did not make Myself known to them."
Rebbe nosson writes in likutey halachot:
"Elokim spoke...I am Hashem... Perush Rashi " this is drawn out from the previous inyan (concept) of what is said, "Why have you harmed this people". And such "Elokim spoke to Moshe saying to him I am Hashem". Because all the diffcult questions about Hashem come from concelment of the truth. The ways of Hashem that are imposible to conceive of are derived from that concealment. those ways are epitomized by thetalmudic discussion of, "ztaddik v'tov lo, ztaddik v'rah lo; and rasha v'tov lo , rasha v'rah lo ect"... and everything is in order to enable free choice, that's the meaning of; "And Elokim spoke", is an aspect of din and so forth. "And saying unto him "I am Hashem", is aspect of rachamim. Meaning that He (Hashem) is informming him (Moshe) that Hashem, is the same as Elokim and it is all one.
Because the midas of rachamim and the midas of the din, in absolute truth, they are one. Only from our prepecstive it is impossible to conceive this! because the inner nature of the truth of His (Hashem) ways and His middas. are impossible to conceive just like it is impossible to understand innner essence of Hashem Himself. and this is the reason for the pasuk, "And I revealed Myself to Avraham, to Yitzchak, and to Yaakov as El Shaddai and My Name Hashem (yud key vav key), I did not reveal or make known to them."
