How the joyful and the sad are to be admonished.
Admonition4. Differently to be admonished are the joyful and the sad. That is, before the joyful are to be set the sad things that follow upon punishment; but before the sad the promised glad things of the kingdom. Let the joyful learn by the asperity of threatenings what to be afraid of: let the sad bear what joys of reward they may look forward to. For to the former it is said, Woe unto you that laugh now! For you shall weep; but the latter hear from the teaching of the same Master, I will see you again, and your heart shall rejoice, and your joy no man shall take from you. But some are not made joyful or sad by circumstances, but are so by temperament. And to such it should be intimated that certain defects are connected with certain temperaments; that the joyful have lechery close at hand, and the sad wrath. Hence it is necessary for every one to consider not only what he suffers from his peculiar temperament, but also what worse thing presses on him in connection with it; lest, while he fights not at all against that which he has, he succumb also to that from which he supposes himself free.
Source: Pastoral Rule (New Advent)