“May it be Your will, YHWH my God and God of my fathers, that You break and destroy the yoke of the evil impulse from our heart. For You created us to do Your will, and we must do Your will; You desire it and we desire it. So who prevents it? The leaven in the dough [i.e., the עֵרֶב רַב (erev rav), mixed multitude, motley throng, cf. BT Qiddushin 71b: ‘Rabbi El’azar said: Ezra did not go up from Babylon (to the land of Israel) until he made it like pure sifted flour: then he went up’]” (JT Berakhot 4:2, 7d).
“When Israel went out of Egypt, they left their domain—alien domain, the domain called חָמֵץ (ḥamets), evil bread. That is why idolatry is called so, and that is mystery of the evil impulse, alien worship, also called שְׂאוֹר (se’or), leaven. This is the evil impulse, for so it functions in the person, like leaven in dough: entering ones innards little by little and then increasing, until the whole body is permeated by it. This is idolatry, of which it is written there shall be no alien god in you (Psalms 81:10)—literally!” (Zohar 2:182a).
“Come and see: In Egypt [Lilit, that beast of the reed (Psalms 68:31)] reigned, and from her issued many kinds of dominion, all in the mystery of חָמֵץ (ḥamets), leavened stuff. Once the blessed Holy One broke her, He removed חָמֵץ (ḥamets) and brought in מַצָּה (matsah). How? By the thinnest thread of all, He broke the ח (ḥet) of this חַיָּה (ḥayyah), beast, and those letters turned into מַצָּה (matsah). Actually, He broke the ח (ḥet) of this חַיָּה (ḥayyah), beast, who is called חָמֵץ (ḥamets). So she is called חַיַּת (ḥayyat), beast, of the reed, for she is easy to break as a reed. How was she broken? By a thread as thin as a hair, He broke the ח (ḥet); it was displaced becoming מַצָּה (matsah). Thus it is written Rebuke חַיַּת (ḥayyat), the beast of, the reed—the blessed Holy One rebuked her, and the ח (ḥet) was broken, turning into ה (he)” (Zohar 3:252a).