The teaching of the Roman Catholic Magisterium on morals is based upon acts, also called human acts. Each knowing choice is an act. Each knowing choice is subject to the judgment of conscience and the eternal moral law of God. Each act is subject to a moral evaluation. Each act is either good or evil. There are no morally neutral acts.

Suppose that someone robs a bank. There are many acts involved in this set of sins. Each immoral act is a sin before God. The person decides to rob the bank, obtains a gun for that purpose, travels to the bank with that intention, threatens the bank teller, et cetera. Each of these acts is a sin by itself. If the person decides to rob a bank, then later changes his mind, he has still sinned gravely by his act of deciding to commit the grave sin of bank robbery.

Suppose that a person commits two acts, one good (moral) and the other bad (immoral). The good act does not justify the bad act, nor does the bad act corrupt the good act, even if the good act occurs immediately before or after the bad act. In fact, if two acts — two knowing choices — occur at the same time, each act stands on its own as to its morality. A husband and wife are taking a walk together (good act), and during the walk, the husband lies to his wife (bad act). The lie does not make the act of taking a walk bad, nor does the good act of taking a walk justify the lie that occurs during the walk.

Good is good, and evil is evil. This distinction is one of the most basic principles of ethics. And it is very commonly rejected or undermined by false teachers within the Church today.

by
Ronald L. Conte Jr.
Roman Catholic theologian and
translator of the Catholic Public Domain Version of the Bible.