192. The circumstances of an act that is only venially sinful in itself also make the act mortally sinful, when there is grave malice in such circumstances. Cases of this kind are the following:
(a) The circumstance of the person committing the sin sometimes changes the malice from light to grave. Example: Unbecoming levity in one in authority may cause serious disrespect for his office and thus be gravely sinful;
(b) The circumstance of the manner in which an act is performed may change it from a venial to a mortal sin, as when the sin is committed out of contempt, or is so coveted that it would be preferred to a grave obligation. Examples: One who violates a law of lesser moment, not because he regards it as bad, but because he wishes to show his disregard of all law and authority; or one who is so attached to games of chance that he is prepared to steal a large sum rather than give them up.
193. The serious harm that is foreseen as a result of venial sin also changes the malice from slight to serious. Examples: One who jokingly annoys another, knowing that this will provoke grave dissensions; or one who tells small lies to persons who are known for their uncharitable distortions and exaggerations; or one who agrees to take too much strong drink knowing from experience that this invariably leads to serious excess.
194. Mortal sins become venial when that which in itself is a grave offense, becomes light by reason of some change in he object or lack of full consent in the subject.
195. A change in the object makes a mortal sin venial: (a) when that which is grave matter objectively, is apprehended through inculpable, or only venially culpable ignorance as light matter (e.g., when an uninstructed child thinks that a serious calumny is only a venial sin); (b) when a sin whose character is serious but whose matter is divisible is small as to matter (e.g,, to be absent from a small part of the Mass on Sunday); (e) when a law whose obligation is grave will cause more than slight inconvenience in a particular case, and thus becomes of light obligation for that case (e.g., to miss Mass on Sunday because of a difficulty that was not unsurmountable, but yet considerable).
196. Lack of sufficient advertence or of full consent makes a mortal sin venial; (a) when without serious fault one does not advert to a gravely sinful act (e.g., a desire of revenge); (b) when without serious fault one does not know or does not think about the grave malice of what one is doing (e.g., to repeat a story, not knowing or not remembering at the time that it is a serious calumny); (c) when on account of considerable excitement, fear or other disturbance, one gives only partial consent to an act that is mortally sinful (e.g., when one, on being suddenly insulted, replies with a serious imprecation).
197. The Distinction of Sins.—There are three kinds of distinction of sins: (a) sins that differ according to theological species, that is, according as they turn or do not turn the sinner away from God as his Last End. There are only two theological species of sin, viz., mortal and venial; (b) sins that differ according to moral species, that is, according to their essences, or the various kinds of finite good to which they turn the sinner. There are many moral species of sins, for example, infidelity, uncharitableness, etc.; (c) sins that differ according to number, but agree according to moral species (e.g., two distinct acts of uncharitable hatred).
198. The criteria for the specific distinction of sins are two:
(a) that which makes sins to differ specifically is the difference of the objects to which they tend, inasmuch as these created goods are out of harmony in specifically different ways with the standards of morality (e.g., pride and gluttony); (b) that by which we recognize the specific difference of sins is the opposition they have to virtues or laws that are specifically different. Thus, pride is opposed to humility, gluttony to temperance—two different virtues.