Nicene and Post-Nicene Fathers, Ser. II, Vol. XI:
The Works of John Cassian.: Chapter XII. That except that wholesome sorrow, which springs up in three ways, all sorrow and dejection should be resisted as hurtful.

Chapter XII.

That except that wholesome sorrow, which springs up in three ways, all sorrow and dejection should be resisted as hurtful.

Wherefore except that sorrow which is endured either for the sake of saving penitence, or for the sake of aiming at perfection, or for the desire of the future, all sorrow and dejection must equally be resisted, as belonging to this world, and being that which “worketh death,” and must be entirely expelled from our hearts like the spirit of fornication and covetousness and anger.