However, the level of the most righteous of 'Tzadikkim' and specifically an Absolute Tzaddik who is repulsed by evil and absolutely hates it is such, that there is not even a possibility at all, for even the smallest existence of evil, to such an extent that it is not even possible for them to commit a sin by accident, which comes from their animal soul of 'Nogah' exerting itself (as is explained in Igeres Hakodesh) as the Possuk states: לֹא יְאֻנֶה לַצַדִיק כָּל אָּוֶן “No wrong shall be caused for the Righteous.”
Absolutely hates it: As is explained in 'Tanya’ that this is the difference between an 'incomplete Tzaddik’, who is also repulsed by evil, however his hatred and disgust of evil are not absolute as it is with the ‘complete Tzaddik’ whose disgust for evil and hatred of evil is absolute.
Possible for them: Tzaddikim in general and more specifically complete Tzaddikim.
Igeres HaKodesh: Of 'Tanya', that the death of the Tzaddikim atones for the sins of the generation, even for the sins that were committed with intent, which is something which stems from the Klipos (husks) of absolute impurity which have no good whatsoever, whilst the sacrificial animals that were brought on the alter only atoned for sins that were committed by accident which stems from the animal soul strengthening itself whilst receiving vitality from Klipas Nogah (the lightest form of impurity which has some 'good' integrated within and can be refined and elevated through being used for holy tasks) which has a mixture of 'good' and Evil.
As the Possuk states: (Proverbs 12:21) לֹא יְאֻנֶּה לַצַדִּיק כָל אָוֶּן וּרְ שָעִּים מָלְאוּ רָע “No wrong shall be caused for the righteous, but the wicked are full of evil.”
No wrong for the righteous: This means that a Tzaddik will not stumble over a sin, even by accident, for even though a sin without intent is not as severe as a premeditated sin transgressed with intent, but since it stems from the animal soul asserting itself which by a Tzaddik has been transformed to good and no longer has any evil, therefore even a sin without intent (Beshogeg) is not possible. In other words someone who is careful about sinning does not even sin by mistake. In the times of the Beis HaMikdosh if someone sinned by mistake he would need to bring an animal sacrifice as a Korbon Chatoss whereas if a person was forced into a situation beyond his control then he does not have to bring a sacrifice and the reason is because if someone sins by accident it is because he was not careful enough.
