Wyjścia 3:15 Komentarz: Rashi, Chizkuni, Ramban & Rashbam

זה שמי לעלם THIS IS MY NAME FOR EVER — The last word is written without ו (so that it may be read לְעַלֵּם and it would mean “this is My Name which is to be concealed”) to suggest: Conceal it (this Divine Name), so that it shall not be read exactly as it is written (but should be read as אדני; cf. Pesachim 50a; Exodus Rabbah 3:7).

:ויאמר עוד אל־הים אל משה: כה תאמר אל בני ישראל, “G-d continued speaking to Moses, saying to him: “thus you shall say to the Children of Israel:” G-d told Moses that it is not appropriate when speaking of G-d to always refer to the name that G-d had just revealed to Moses. This we know already from a mortal king, whom the people applaud when shouting: “long live the king,” without mentioning the king’s name, as this would be discourteous. If a mortal king is not always referred to by his personal name, how much less so is it seemly to refer to the King of Kings on all occasions by His personal name? Whenever anyone will speak to you about the Exodus from Egypt, he will refer to G-d simply as: “Hashem, the G-d of your fathers.” {Mechilta, Pischa, chapter 16)

AND THIS IS MY MEMORIAL UNTO ALL GENERATIONS. This refers back to the G-d of Abraham, the G-d of Isaac, and the G-d of Jacob, for the covenant [of G-d] with the patriarchs will never be forgotten, and throughout all generations whenever the children of Israel will mention [in prayer], “the G-d of Abraham, Isaac, and Jacob,” G-d shall hear and answer them.²³¹Psalms 55:20. The verse here thus states: “Thus shalt thou say unto the children of Israel. Whenever you mention Me in prayer say thus: ‘G-d of Abraham, G-d of Isaac…’ This is My memorial unto all generations.”
By way of the Truth, [the mystic lore of the Cabala], this is My name forever refers to the G-d of Abraham, the G-d of Isaac. And this is My memorial refers to the expression, and the G-d of Jacob. This is the reason He added here the letter vav — [v’zeh zichri (‘And’ this is My memorial)].²³²It is to indicate that this is the preponderant Name in the memorial (Bachya). This is the sense of the expression, zichri l’dor dor, [with the words l’dor dor written] defectively, [i.e., without a vav between the dalet and the resh]. The person learned in the mysteries of the Torah will understand.