561. With reference to penalty, four kinds of laws can be distinguished.
(a) Purely preceptive laws are such as oblige under pain of sin, but not under pain of punishment. There are church laws of this kind (such as the command to assist at Mass on Sunday), and there are also some civil laws that do not oblige under penalty (e.g., statutes governing the age for legal marriage, for, if a couple misrepresented their age, they might be prosecuted for the misrepresentation, but not for the act of marriage).
(b) Purely penal laws are such as oblige under pain of juridical fault and punishment, but not under pain of sin (e.g., a law that punishes negligence in driving as defined by itself, even though there be no moral culpability involved).
(c) Mixed laws disjunctively are such as oblige under sin either to obey the law or to suffer the penalty (e.g., a law that commands one either to get a license before fishing or hunting, or to pay a fine if caught doing these things without a license).
(d) Mixed laws conjunctively are such as oblige under pain of both sin and punishment (e.g., the laws that forbid injustice and command the punishment of transgressors).
562. There is no question about the existence of laws of the first and fourth classes just described, but some authorities argue against the existence of the other two classes, maintaining that a law that does not oblige in conscience is an impossibility. They argue: (a) the teaching of scripture and of the Church supposes that all just laws oblige in conscience; (b) the lawgiver holds the place of God, and hence one cannot offend against the law of man without offending God; (c) human law, being only a reaffirmation or determination of the higher law, obliges in conscience like the law on which it is based; (d) directions of a superior that do not oblige under sin are counsels rather than laws.
563. To these and similar arguments the defenders of the existence of penal laws reply: (a) such laws do not oblige in conscience, under pain of sin and of offense to God, to do or to omit as the law prescribes, just as a vow which gives one the option of not playing cards, or else of giving each time an alms, does not bind one in conscience not to play cards; (b) but those laws do oblige one in conscience to respect their juridical value, not to resist their enforcement, and to pay the penalty of violation, just as the vow mentioned obliges one in conscience to give an alms each time one plays cards. The Church recognizes penal laws (see 450), and there is no reason why civil law may not be penal.
564. Even when the transgression of a purely penal law is not sinful by reason of the civil law, it will frequently, if not usually, be sinful by reason of repugnance to the law of God. Thus: (a) the transgression will be sinful, if there is a wrong intention (such as contempt for the law) or wrong circumstances (such as culpable neglect or some inordinate passion); (b) the transgression will be sinful, if one foresees or should foresee evil consequences, such as scandal (see 96).
565. It is generally admitted that some civil laws are purely penal, since they impose penalties for fault, negligence, or responsibility that is only juridical at times. Examples: A law that imposes a fine on all motorists caught driving over a certain speed limit, even though they be free of moral guilt; or that makes the owner of a car pay damages for injuries caused while it was used by his chauffeur.
566. Even these laws oblige under sin to some extent. (a) The transgressor is morally bound to the penalty prescribed by law, after sentence has been passed; and such penalties are just, for the common good requires them. Example: The speed violator is held to pay the lawful fine when it has been imposed. He may have been guiltless of sin, but the fine makes him more careful the next time. (b) The officers of the law are morally bound to apprehend and convict transgressors.