וכי דנין אפשר משאי אפש'?
The Gemara asks: And does one derive the halakha of the possible from the impossible?
MISHNA: If a court erroneously issued a ruling permitting the Jewish people to violate one of all the mitzvot that are stated in the Torah, and an individual proceeded and performed that transgression unwittingly on the basis of the court’s ruling, then whether the judges performed the transgression and he performed it with them, or whether the judges performed the transgression and he performed it after them, or whether the judges did not perform the transgression and he performed it alone, in all these cases the individual is exempt from bringing an offering. This is due to the fact that he associated his action with the ruling of the court.