Tanya for the 25th of Kislev, כ''ה כסלו, leap year

It is only in this legal sense that the term tzaddik is applied to one who performs more good deeds than evil. A true Tzaddik is one who has completely eradicated the evil from within. Every Jew has two souls, one stemming in G-dliness, and the other in impurities. Every animal soul also has its unique nature, based on its unique source element in creation.