When Hashem charged Moshe with the mission of acting as the go'el of Bnei Yisrael, Moshe responded (3:11)
וַיֹּ֤אמֶר מֹשֶׁה֙ אֶל־הָ֣אֱלֹקים מִ֣י אָנֹ֔כִי כִּ֥י אֵלֵ֖ךְ אֶל־פַּרְעֹ֑ה וְכִ֥י אוֹצִ֛יא אֶת־בְּנֵ֥י יִשְׂרָאֵ֖ל מִמִּצְרָֽיִם
To which Hashem responded:
וַיֹּ֙אמֶר֙ כִּֽי־אֶֽהְיֶ֣ה עִמָּ֔ךְ וְזֶה־לְּךָ֣ הָא֔וֹת כִּ֥י אָנֹכִ֖י שְׁלַחְתִּ֑יךָ בְּהוֹצִֽיאֲךָ֤ אֶת־הָעָם֙ מִמִּצְרַ֔יִם תַּֽעַבְדוּן֙ אֶת־הָ֣אֱלֹקים עַ֖ל הָהָ֥ר הַזֶּֽה
How does that answer the question? How does the fact that there will be a kabbalas haTorah serve as a response to מִ֣י אָנֹ֔כִי?
Moshe later complained that Bn"Y will not believe his message (4:1)
וַיַּ֤עַן מֹשֶׁה֙ וַיֹּ֔אמֶר וְהֵן֙ לֹֽא־יַאֲמִ֣ינוּ לִ֔י וְלֹ֥א יִשְׁמְע֖וּ בְּקֹלִ֑י
Why did he doubt them? Yosef had told them before he died (Braishes 50:24)
וַיֹּ֤אמֶר יוֹסֵף֙ אֶל־אֶחָ֔יו אָנֹכִ֖י מֵ֑ת וֵֽאלֹקים פָּקֹ֧ד יִפְקֹ֣ד אֶתְכֶ֗ם וְהֶעֱלָ֤ה אֶתְכֶם֙ מִן־הָאָ֣רֶץ הַזֹּ֔את אֶל־הָאָ֕רֶץ אֲשֶׁ֥ר נִשְׁבַּ֛ע לְאַבְרָהָ֥ם לְיִצְחָ֖ק וּֽלְיַעֲקֹֽב
The people had this tradition that the use of the code words פָּקֹ֧ד פָּקֹ֧דתי would be a sign that the go'el was legitimate. So why would they not believe if Moshe had the right code?
R' Mordechai Greenberg, the nasi ha'yeshiva of Kerem b'Yavneh, explains based on the writings of R' Kook, that Bn"Y is singled out from the nations of the world in two respects: 1) we are a moral, law abiding people, not like the primitive tribes of the past; 2) we have a spiritual connection with Hashem beyond what other nations have. Even if other nations attain culture, abide by laws, become civilized, and become our equal with respect to #1, we still excel above them with respect to #2.
This double-blessing is the meaning of Hashem's promise to Yaakov (Braishis 46:4)
אָנֹכִ֗י אֵרֵ֤ד עִמְּךָ֙ מִצְרַ֔יְמָה וְאָנֹכִ֖י אַֽעַלְךָ֣ גַם־עָלֹ֑ה
The double-אָנֹכִ֗י is a two fold promise. One is the promise that Hashem will be with Bn"Y even in the tumah of Mitzrayim and preven them from descending to the level of primitiveness and lawlessness of a backward society. Secondly, there is the promise that redemption will bring them close to Hashem, to spiritual heights like no other people have reached.
And this is the meaning of the promise of פָּקֹ֧ד פָּקֹ֧דתי, also doubled. A redemption that just releases the people from the chains of bondage without giving their lives spiritual content and meaning is insufficient -- the go'el must deliver both.
This was Moshe's challenge to Hashem. "You Hashem promised אָנֹכִ֗י אֵרֵ֤ד עִמְּךָ֙ מִצְרַ֔יְמָה וְאָנֹכִ֖י אַֽעַלְךָ֣ גַם־עָלֹ֑ה. That role can only be fulfilled by You, but מִ֣י אָנֹ֔כִי, I or any other human being cannot be that אָנֹ֔כִי."
And this is why Moshe doubted that the people would believe. There was no magic to saying the right code words. Those words reflected the double promise, the promise of both physical and spiritual redemption. That is what Moshe thought he would be unable to fulfill. To break the shackles of slavery is one thing, but to give the nation a spiritual identity -- that's a different story.
Hashem's response to Moshe is that indeed He is the One who will fulfill the promise of אָנֹכִ֖י אַֽעַלְךָ֣, but it will be done through Moshe, כִּֽי־אֶֽהְיֶ֣ה עִמָּ֔ךְ.
The culmination of that promise of אָנֹכִ֖י אַֽעַלְךָ֣ will take place at Sinai, where the people will hear אָֽנֹכִ֖י֙ ה׳ אֱלֹקיךָ אֲשֶׁ֧ר הוֹצֵאתִ֛יךָ מֵאֶ֥רֶץ מִצְרַ֖יִם מִבֵּ֣֥ית עֲבָדִֽ֑ים.