Exodus 3:15

And the Lord said again unto Mosheh, Thus shalt thou speak to the sons of Israel, The God of your fathers, the God of Abraham, the God of Izhak, and the God of Jakob, hath sent me unto you. This is His Name for ever, and this is His Memorial to every generation and generation.

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.. 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)]. 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.

ויאמר עוד אלוקים, to Moses “it is not fitting that when referring to Me the Israelites should always do so by calling Me by this name (title), just as it is not fitting for people always to refer to their regional king by his most illustrious title. It is good enough for you to refer to Me as אלוקי אבותיכם,ה', “the G’d of your patriarchs, etc.” This name includes within it that G’d is master and king. When one addresses a king of flesh and blood, one does not spell out his full titles, but contents oneself with saying: “long live the King!” (Samuel I 10 24) Or, when referring to an order given by the king, one simply says: “the King commanded me etc.,” without adding the King’s other titles (Samuel I 21,3).

זה שמי לעולם וזה זכרי לדור ודור, the name אהיה אשר אהיה, “the Eternal” which I told you in verse one (14) is My most illustrious title, a reference to My essence, (the ineffable name) whereas the name(s) I told you in verse two (verse 15) is a description of My being Royalty. [The author continues to remind us that it is in the nature of things that G’d refers to Himself slightly differently from the way His creatures refer to Him even when using the same basic “name.” Whereas G’d refers to Himself in the first person, i.e. starting with the letter א, when His creatures refer to Him by the same “name,” they must commence the spelling of that name with the letter י as one refers to a third person. In addition, by using the alphabet in reverse order i.e. ת-ש ר.ק. G’d would spell His own name אהי'ה as תצמ'ץ, and all the other names of G’d with which we are familiar would similarly appear with the letters based on starting with the letter ת in a descending order. Ed.]

ויאמר עוד אלוקים אל משה כה תאמר אל בני ישראל, the Beney Yisrael that G’d refers to here are the elders of the people. (according to Rashi the people at large would not understand such thoughts.)

ה' אלוקיכם, this is also the G’d of your patriarchs in addition to being the G’d possessing these virtues just mentioned. He had concluded a covenant with your patriarchs including all their offspring, so that this is part of My definition (name) זה שמי לעולם, forever as well as the name He already was known by previously before this additional attribute through the covenant with the patriarchs.

זכרי לדור ודור, this is what wise men have figured out for themselves already since time immemorial that there must be a prime Cause, an eternal Being, not subject to change, i.e, to aging, weakening.