Parshat Vaera relates G-d introducing the name Kel Shakkai (spelling was modified, out of respect for the actual name) to Moshe (6:2-3), and tells him that the forefathers all knew Him as Kel Shakkai, but that now I am YHVH (we don’t know how to pronounce that, so we say Hashem). What is G-d telling Moshe? What is the difference between G-d’s different names, and what will now change?
Beth Lesch of AlephBeta pieces together several clues that can combine as an answer to our question. She points out that the first time Kel Shakkai is introduced is when G-d appeared to Avraham (17:1). There, Avraham is instructed to walk before G-d. How does one walk before G-d? Skip to Yakov, who on his deathbed says “The G-d before whom my fathers Avraham and Yitzchak walked, the G-d who has been my shepherd.” (Gen. 48:15) G-d led as a shepherd leads, from the rear. You see, to herd sheep, you don’t lead from the front, for they will not follow. You lead from behind, the flock senses movements from behind them and moves as a group. It’s the perfect metaphor for how G-d guides us, as Kel Shakkai, and asks us to be his sheep, under His protection. The change in our Parsha is from G-d replacing His typical position of guiding us silently and subtly to guiding the Jews out of Egypt with miracles and spender. G-d’s attributes are used as needed, both in the times of the exodus, and in our current lives. Whether we’re being gently guided or boldly led, guidance is always there when we need it.