And see, with respect to the first group, it says: כִּי אֱוִיל עַמִּי אוֹתִי לֹא יָדָעוּ, "for My people are stupid, they do not know me (Yeremyahu 4:22)." It describes the majority of the people, who are simply called (in the verse) "My people."
And with respect to the third group, they occupy themselves with the mysteries of the Torah, and it secrets, and are called sons, בָּנִים. As is written in the Tikkunim (Hakdama, p. 4): the Ephrochim are Baalei HaMishnah, the sons are Baalei Kabbalah. And about them, it says: בָּנִים סְכָלִים הֵמָּה וְלֹא נְבוֹנִים, "they are foolish sons, and they are not discerning (Yeremyahu 4:22)," because they occupy themselves with the Chochmah of the Truth, according to what comes up in their short view, and in their weak studies. They do not enter the depth of a matter, to understand it in its truth, similar to what is said about the Am HaAretz.
And with respect to the group of the Chachamei HaPshat, those who despise the Chochmah of the Truth, which is called Ets HaChaim, and eternal life, and occupy themselves with the simple stories, and with the simple meaning only. They say that in the Torah there is nothing but the simple meaning, Chas V'Shalom. About them, it says: חֲכָמִים הֵמָּה לְהָרַע וּלְהֵיטִיב לֹא יָדָעוּ, "they are wise at doing evil, but know not how to do good (Yeremyahu 4:22)," because they hate the Ets HaChaim, HaKadosh Baruch Hu does not help them. And they decide about the simple things of Ets HaDaat Tov v'Ra, and turn it into Ra, evil, declare impure what is pure, make Assur what is Mutar, declare Pasul what is Kosher, their hands produce many failed rulings, in their many sins.
Chaim Vital, Hakdamah to Ets HaChaim (Shaar HaHakdamot), 9-10.
כִּי אֱוִיל עַמִּי אוֹתִי לֹא יָדָעוּ בָּנִים סְכָלִים הֵמָּה וְלֹא נְבוֹנִים הֵמָּה חֲכָמִים הֵמָּה לְהָרַע
