Title II. Penal Law and Penal Precept
Can. 1313 §1. If a law is changed after a delict has been committed, the law more favorable to the accused is to be applied.
§2. If a later law abolishes a law or at least the penalty, the penalty immediately ceases.
Can. 1314 Generally, a penalty is ferendae sententiae, so that it does not bind the guilty party until after it has been imposed; if the law or precept expressly establishes it, however, a penalty is latae sententiae, so that it is incurred ipso facto when the delict is committed.
Can. 1315 §1. A person who has legislative power can also issue penal laws; within the limits of his competence by reason of territory or of persons, moreover, he can by his own laws also strengthen with an appropriate penalty a divine law or an ecclesiastical law issued by a higher authority.
§2. The law itself can determine a penalty, or its determination can be left to the prudent appraisal of a judge.
§3. Particular law also can add other penalties to those established by universal law for some delict; however, this is not to be done except for very grave necessity. If universal law threatens an indeterminate or facultative penalty, particular law can also establish a determinate or obligatory one in its place.
Can. 1316 Insofar as possible, diocesan bishops are to take care that if penal laws must be issued, they are uniform in the same city or region.
Can. 1317 Penalties are to be established only insofar as they are truly necessary to provide more suitably for ecclesiastical discipline. Particular law, however, cannot establish a penalty of dismissal from the clerical state.
Can. 1318 A legislator is not to threaten latae sententiae penalties except possibly for certain singularly malicious delicts which either can result in graver scandal or cannot be punished effectively by ferendae sententiae penalties; he is not, however, to establish censures, especially excommunication, except with the greatest moderation and only for graver delicts.
Can. 1319 §1. Insofar as a person can impose precepts in the external forum in virtue of the power of governance, the person can also threaten determinate penalties by precept, except perpetual expiatory penalties.
§2. A penal precept is not to be issued unless the matter has been considered thoroughly and those things established in cann. 1317 and 1318 about particular laws have been observed.
Can. 1320 The local ordinary can coerce religious with penalties in all those matters in which they are subject to him.