"And they said: 'This Israel is your G‑d who took you out of Egypt'." (Ex. 32:4)
"They" is the 'Mixed Multitude,' which is why it says "your G‑d" and not "our G‑d."
(see Rashi on verse)

The Mixed Multitude derive from the evil of Moses….

[As we have explained elsewhere,] the Mixed Multitude derive from the evil [aspect] of Moses. They issued prematurely and were not properly rectified [first], so they sinned.

When the Jews, led by Moses, left Egypt, Moses acceded to take along a "mixed multitude" of non-Jews with them. Although his intentions were good, these people had not been fully educated about the ways of Judaism and the path of the Torah, and so they made numerous errors in judgment throughout Israel's trek in the desert, often drawing the Jewish people into their errors as well.

Evil can be defined as consciousness not sufficiently oriented toward and focused on G‑d - or, worse, oriented away from or against G‑d. Just as with people, who must undergo a selfish period of childhood in order to develop their sense of self before emerging into the mature, adult world, so must any revelation of Divinity, or any soul, undergo a maturation process before it can descend into the world. Although the soul will mature again during its lifetime as it goes through childhood, etc., this is a second stage of development. Thus, to a certain extent, the character of the individual is already developed during its fetal life.

The Mixed Multitude thus reflected this idea of premature introduction into holiness. Insecure in their sense of self, they were not ready to abandon it in favor of the truth to which they were being elevated.

Moses, as a leader, should have known that this was the case. But his acceptance of the Mixed Multitude reflected a weakness on his part, an unwarranted tolerance and acceptance of that which is imperfect and unripe, erroneously allowing it to take part in mature, adult life before its time. (Perhaps this over-fascination with the raw, the untamed, and the immature echoes Isaac's fascination with and preference of Esau over Jacob, as well as modern society's worship and indulgence of youth at the expense of its reverence and appreciation of the wisdom of age.)

G‑d did not want to accept these unfit converts. [Had they not joined the Jewish people], there would have been no death or exile, as it is written, "[The tablets were the work of G‑d, and the writing was the writing of G‑d,] chiseled on the tablets." (Ex. 32:16)

When the Torah was first given, the spiritual impurity caused by the sin of the Tree of Knowledge was removed from the world. Thus, the Hebrew word for "chiseled", "charut", can be interpreted to mean "freedom" (in Hebrew, "cheirut"); the tablets freed the world from the sentence of death and its spiritual analog, exile. (Avot 6:2; Eiruvin 54a; Shemot Rabbah 32:1) The Mixed Multitude, however, perpetrated the sin of the Golden Calf, which reintroduced this impurity or self-orientation into the world.

But Moses accepted them, thinking that it would be good to absorb them into holiness.

This way, Moses reasoned, their unrefined power could be harnessed for holy purposes. Their desire to join the Jewish people seemed to indicate their readiness for this.

Aspects of his soul return as the leader of each generation in order to rectify the spiritual heirs of the Mixed Multitude….

[He] especially [wanted to accept them] because they were somewhat important to him, as it is written "the people in whose midst I am" (Num. 11:21), and "the people at your feet" (Ex. 11:8). Thus, he sought to rectify them. But on the contrary, they ruined Israel, as it written, "Go, descend, for your people who you brought up out of Egypt have corrupted..." (ibid. 32:7). It does not say "have been corrupted" but "have corrupted", meaning, "have corrupted others," i.e. Israel.

In this verse, the verb "corrupt" is transitive. Furthermore, G‑d tells Moses about his people, that he, not G‑d, brought up out of Egypt, referring to the Mixed Multitude.

Moses therefore had to die, in order to ascend on high and receive G‑d's beneficence. There is therefore no generation without [a leader like] Moses.

In order to right the wrong he caused, Moses' trans-generational job is to rectify the ongoing impurity of the Mixed Multitude, until it is fully matured. He therefore belongs spiritually to the pre-redemptive generation of the desert and could not pass over the Jordan river to lead the next generation in the conquest of the Land of Israel. Aspects of his soul return as the leader of each generation in order to rectify the spiritual heirs of the Mixed Multitude.

In order to do this, his soul, each time, has to accrue extra spiritual power, and this it does by staying in the womb of Imma for a longer than usual period, as the Arizal explains in Part 2.

Translated and adapted by Moshe-Yaakov Wisnefsky from Sefer HaLikutim; subsequently published in "Apples From the Orchard."

Reprinted with permission from Chabad of California. Copyright 2004 by Chabad of California, Inc. All rights reserved, including the right to reproduce this work or portions thereof, in any form, without permission, in writing, from Chabad of California, Inc.