1. The Object, or thing to be done, is good.
An act must be good, or at least morally indifferent. Some acts are always and everywhere evil (intrinsic evils) and may never be done, for example, blasphemy, abortion and adultery. Doing them can never be made into good acts, by a good intention or circumstances.
2. The End, or intention for doing it, is also good.
An evil intention destroys the moral goodness of an otherwise good act, for example, doing an act of charity or religion in order to be seen by others. Human beings often do things with mixed motives, so this applies to the primary intention for which the act is done. Lesser mixed intentions, e.g. vanity, can diminish the goodness of the act without destroying it.
3. The Circumstances are also taken into account and are fitting.
Unfitting circumstances can also lessen, and even destroy, the moral goodness of an otherwise good act. For example, unless the common good requires it, fraternal correction should generally be given privately. To give it publicly without necessity, or in an unfitting manner, are among the circumstances that could reduce or destroy the moral goodness of the act.
A Morally Good Act Will Be Prudent
Prudence is the virtue which disposes practical reason to discern our true good in every circumstance, and to choose the right means of achieving it: "the prudent man looks where he is going" (Prov. 14:15).
Prudence is the Queen of the Virtues. It governs the knowledge, judgment and execution of our acts. It helps us decide whether to act, in what circumstances, and how to carry the act through to the end. Prudence, therefore, concerns the beginning, the middle and the end of moral action.
St. Thomas Aquinas identifies 8 integral parts of prudence, elements which make for a perfect moral judgment and its execution. Memory of the past, Understanding of the present, Docility to be taught, Shrewdness in making a quick conjecture, Reasoning from one thing to judgment regarding another, Foresight regarding what is befitting the end, Circumspection appropriate to the situation, and Caution to avoid obstacles to attaining the end.
A failure in prudence is the sin of imprudence. A good deed can be tarnished by imprudence, so that its value is not altogether lost but is diminished (venial sin). It can also so detract from the goodness of the end so that it perverts it. If the matter of the act is grave, the sin would be grave; if the matter is slight, the sin would be venial.
Even good people commit imprudent acts, considered as imperfections of otherwise good actions. Thus, Proverbs 25:6 tells us, “a righteous man falls seven times, and rises again,” and Our Lord taught us to ask forgiveness daily for our daily faults, that we in turn might be forgiven by the Father.
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