Tanya for the 12th of Adar 1, י''ב אדר א

The Alter Rebbe now proceeds to suggest various lines of reasoning that the beinoni may use in order to humble and crush his spirit—and thereby the sitra achara of his animal soul. The first of these follows from the point just concluded, that the personality of the beinoni is, in fact, an expression of the sitra achara—the animal soul.