237. Sinful joy is an act of the will by which one takes delight in sins already committed by oneself or by others. We must distinguish between sinful joy and joy about things that are sinful.
(a) Sinful joy rejoices over the iniquity contained in past acts, either because it loves that iniquity in itself, or because it loves it as the cause of some gain. Examples: An unjust and revengeful man rejoices when he thinks of the oppression he exercised against some helpless person who had incurred his wrath. A criminal recalls with joy the perjuries by which his helpers secured his escape from justice.
(b) Joy about things that are sinful or consequent on sin rejoices, not that what was done was wicked, but over other circumstances that were good or indifferent. Examples: An employer admires in the conduct of a dishonest employee, not the injustice committed, but the shrewd manner in which the fraud was perpetrated. A bystander is very much amused to witness a fight, not because he likes discord, but because the acts and remarks of the fighters are comical. A man rejoices when he hears that a friend has committed suicide and made him his heir, if the joy is confined to the second part of the news.
238. The moral gravity and species of evil rejoicing has the same character as the past sins that are its object (see 70 sqq.). For to rejoice over sin is to approve of it, and therefore to be guilty of it in will. Example: A prisoner who, to overcome melancholy, thinks over the times he became intoxicated in the past, is guilty again of those sins, with their number and circumstances adverted to.
239. What has been said about evil rejoicing applies likewise: (a) to boasting over sin committed, because this implies complacency in the sin; (b) to sorrow over sin omitted, because this means that one approves of sin rather than virtue.
240. To be sorry because one performed good that was not obligatory is not sinful of itself, but it may become so by reason of the evil motive of the sorrow, or of the danger of sin. Examples: If a person is sorry that he performed many unnecessary devotional exercises, because he injured his health thereby, his sorrow is not sinful. If he grieves over this because he now dislikes religion, his sorrow is made bad by his evil motive. If he regrets that he married, this is sinful if it leads him to neglect the duties of his state and commit injustice.
241. Evil desires are acts of the will by which one deliberately intends to commit sin in the future. They are of two kinds, viz., absolute and conditional: (a) absolute or efficacious desires are those in which the mind is fully made up to carry out the evil design, come what may; (b) conditional or inefficacious desires are those in which the purpose to commit sin hinges upon the fulfillment of some event or circumstance that is explicitly or implicitly willed.
242. Absolute evil desires have the same moral gravity and species as that to which they tend (i.e., they take their character from the object, end and circumstances). Example: He who plans to steal a large sum from a benefactor in order to be able to live in idleness and dissipation, sins gravely against justice, and is also guilty of ingratitude and intemperance, for he has committed all these sins in his heart.
243. Conditional evil desires, if they are indeliberate and express rather the propensity of nature than the considered will of him who makes them, are not formally sinful. Examples: A poor man who unthinkingly wishes that stealing were lawful; a sufferer who under the influence of pain wishes that the Almighty had not forbidden suicide.
244. Conditional desires, if made deliberately, are of two kinds. (a) There are some desires in which the condition willed (e.g., if this were not a sin, if this were lawful, if this were allowed by God, etc.) takes away the malice of the act desired, since some laws may be dispensed or changed. Examples: “Would that God had not pronounced against taking the property of others!” “I would stay away from church, if this were not Sunday.” Desires of this kind are not sinful on account of their object, which is not really wished, but on account of their end, or their lack of useful purpose, and of the danger that the conditional may become absolute. (b) There are other desires in which the condition does not take away the malice of what is desired, either because the condition is not at all concerned with the malice, or because it wishes something to become lawful which even God cannot make lawful. Examples: “I would steal, if this could be done safely.” “I would blaspheme, if God permitted.” These desires partake of the malice of the things that are wished.