482. Of course, what was said in the preceding paragraph has to do only with single laws, and with what is strictly needed for the fulfillment of the law. Hence: (a) he who sins because of the way in which he fulfills one law, violates another law (e.g., one who is willingly, though not entirely, distracted at Mass, obeys the church law of assistance at Mass on Sunday, but he disobeys the divine law that he worship God devoutly);
(b) he who has less devotion in obeying a law than he might have had, does not deserve reprehension as a transgressor, but his conduct is less praiseworthy.
483. Interpretation.—The meaning of interpretation and its various species were explained above in 315 sqq.
484. As to the force of interpretation of church laws, the following points must be noted:
(a) Authentic interpretation given in the form of law has the force of law; if it is merely declarative of words of the law certain in themselves, it does not need promulgation and is retroactive; if it is supplementary, it needs promulgation and is not retroactive, since it is a new law (Canon 17, Sec. 2);
(b) Authentic interpretation given in the form of judicial sentence or of rescript in a particular matter has not the force of law; and it obliges only the persons and affects only the things concerned (Canon 17, Sec. 3);
(c) Usual interpretation has the force of law when it is given through a legitimate custom (see above, 391 sqq.), for “custom is the best interpreter of law”;
(d) Doctrinal interpretation has not the force of law, since it does not proceed from the lawgiver. Its value depends on the reasons and the authority by which it is supported. When all the doctors agree, their interpretation is morally certain; when they disagree, the various interpretations have more or less probability.
485. Rules for Doctrinal Interpretation.—(a) The words must be understood in their proper sense according to text and context, unless this be impossible; if doubtful, they must be judged according to parallel places in the Code, the circumstances, reason of the law, and the mind of the lawgiver (Canon 18).
(b) Things that are burdensome should be understood in their most restricted sense (Canon 19), things that are favorable in their widest sense. Thus, the censure pronounced against simony is understood in the narrow sense of simony against the divine law; a privilege granted to the clergy is understood in the wide sense as given to all the clergy.