Sixth and Ninth Commandments: "You shall not commit adultery. You shall not covet your neighbor's wife."

1. Sins against Chastity

The sixth and ninth commandments forbid us to try to seek out sexual pleasure or to accept it when temptation offers it, outside of marriage. St. Paul told the licentious Corinthians (1 Cor 6. 19-20: "Do you not know that your body is the temple of the Holy Spirit, whom you have from God, and you are not your own. For you have been bought at a price [the price of redemption]."

Not only external acts which by nature are apt to arouse sexual pleasure themselves are forbidden outside of marriage; also thoughts and desires deliberately aroused, or accepted when they come unbidden are sinful. But a good person may have a long siege of such thoughts: as long as he/she tries to get rid of them each time he/she notices them (there can be distractions), there will at least be no mortal sin. Sometimes when one is occupied with something else, such a thought may slip into the brain and unroll itself like a movie. It may run some time until a sort of wake-up point where the person says to self: I must not have this" and then gets busy against it. Up to that point there is never mortal sin.

Masturbation turns one back into the shell of self in which one started life, and so makes real love difficult, gives a poor forecast for success in marriage.

Homosexual acts are most gravely wrong, and the more so if the sinner asserts they are good. St. Paul painted a sad picture of the vices of the gentiles in Romans chapter 1, and made homosexuality the centerpiece. He added (1:32) that the lowest depth is to not only sin, but to call sin good.

It is not a sin to have homosexual temptations, provided one does not give into them.

Contraception is really only mutual masturbation. For the use of sex is divinely ordained first of all to propagate the race. To deliberately rule that out is to fly directly into the face of God's plan. Experience shows that where contraception is common, abortion tends to follow as a sort of backup.

The same is not to be said of Natural Family Planning: it makes legitimate use of the characteristics God Himself has built into our nature. Its reliability is over 99%, as high as that of artificial methods. And there are no bad side effects.

Experience shows that to use it strengthens marriage. The reason is this: any pleasure, even sex, can grow dull if we take it very constantly. Some small abstention, as needed for NFP, helps to revive the pleasure of lawful sex.

Fornication is having sex outside marriage when both parties are unmarried. Adultery is the same except that one or both are married to someone else. It is a violation not only of chastity but of justice towards the spouse.

2. True Conjugal Love

Vatican II has taught (Constitution on the Church in the Modern World #49): "The actions by which the spouses are intimately and chastely united are honorable and worthy, and if done in true human fashion, signify and promote the self-giving by which the couple gladly and gratefully enrich each other." They can even be meritorious if done in accordance with God's plan. The same document added (#50): "Marriage and conjugal love are by their nature ordained to the procreation and education of offspring." We notice there are two purposes, procreation, and mutual love. Both are intended by God, yet in such a way that the procreation is primary, since the promotion of love "is by nature ordained to" procreation, i.e., is secondary to it.

It is only in marriage that children can receive the formation, love and care that they need. This is why sex outside of marriage is so wrong.

To separate the two functions, procreative and unitive is wrong, e.g., in test-tube babies.

Carried out according to Our Father's plan, marriage can lead to real growth in holiness, as we shall explain later on.

3. The Means to Chastity

Much prayer, especially to the Blessed Mother (particularly her Rosary) is needed along with keeping watch over what one sees, reads, dreams about. The thought of death and judgment helps greatly, and frequent use of the Sacrament of Penance and the Holy Eucharist are important.

Mortification of the body, by giving up legitimate things is practically indispensable as a help. At a time when temptation is strong, it helps to get into the company of others (unless it be the person of the opposite sex who is the cause of temptation). If that is not possible, getting occupied with something that readily holds one's interest, such as absorbing reading is important. The more we get our attention onto anything else, the less power the temptation has. Many find it helpful to say to themselves: "I will keep pure just this one time." They do not mean to fall the next time, but this is a way of lightening the psychological difficulty.

It is important to realize and to talk it through with a prospective mate, that since love is the desire for the well-being and happiness of another for the other's sake, to use the other for sensory gratification is not love. It is closer to the opposite, for it puts both into such a state that if death should come, the person would never be happy again, would be eternally wretched. That is the opposite of willing well-being to another. And real love is rather unlikely to develop when two indulge in much premarital sex. It will feel like love, but will only be chemistry.

Commandments VII, X and VIII

Seventh and Tenth Commandments: "You shall not steal. You shall not covet anything that belongs to your neighbor."

1. Justice and Private Property

The seventh and tenth commandments imply the right to private property, by forbidding taking what belongs to others or even desiring to do so.

The experience of "communist" countries shows that without this right, incentive to work hard enough to keep the country operating well is lacking.

There is, however a social aspect to private property, of which we shall speak soon.

2. Stealing, Theft, Robbery, Dishonesty, Gambling

Theft is the secret taking of an object against the reasonable wishes of the owner. If it is taken openly instead of secretly, it is called robbery; if something is stolen by the use of deception or fraud it is called cheating.

It is not only those who do these things that are guilty, but also those who advise or help them, those who buy, sell or keep stolen goods knowing that they are such, those who do not return what they have found (when it is possible) or borrowed, those who do not pay their just debts, and those who beg when they have no need, for in that way they are defrauding those who really are in need.

Cheating is a form of fraud. To give false weights or measures or practice any other deceit is also cheating. Those who take pay and do not give the proper measure of the work for which they have contracted are also guilty of cheating or fraud. For we should not look down on honest work. Our Lord Himself worked as a carpenter for most of His earthly life.

If an employee or servant disposes of the property of the employer without his/her approval he/she is guilty of fraud. It is also fraud for them to waste time, equipment, or material.

All these forms of stealing, robbing, etc. can be mortally sinful if the amount or value taken is equal to the day's wages of the person from whom it is taken. If it is taken from an extremely rich person even if it is not more than what that person makes in a day, if extremely large, there can be grave sin. The same is to be said of stealing etc. from a business firm.

Stealing etc. require restitution, for to retain the stolen goods is to continue the sin. It can never be forgiven until the person either actually gives back or prepares to do so.

Gambling is sinful if one risks more than he/she can really afford, or money needed for the support of the family. Gambling is also sinful if dishonest means are used by the gambler, or by the one who offers gambling.

Betting is similar: it is an agreement in which two or more agree to give a prize to whichever one makes the right guess on some future thing. It would be wrong if not all parties understood the agreement in the same way, or if one is not really uncertain about the outcome.

Gambling and betting can become an addiction.

3. Social justice

The right of private property is not without limits imposed by social justice, e.g. it would be wrong if an employer were to offer an inadequate wage and say: "If you do not like it, go elsewhere" when actually there is nowhere to go to get proper pay.

Outside of unusual conditions, an employer is bound to offer a family living wage for full time employment.

All have an obligation to help the poor. There is a sort of scale: in one column we list the various degrees of need, from the desperate need which if not met at once means death, to minor degrees of want. In the other column we list the various degrees of difficulty in meeting the needs of the other. If one would otherwise actually starve, he may even take what food is strictly necessary without permission, and it would not be sinful. At the other end of the scale, where there is merely ordinary need, we cannot normally specify that a particular person must help, when there are others who could also help.

However what we have just said concerns the minimum that is demanded to avoid sin. For real Christian charity and for real happiness in this life, Our Lord advises us to go much farther, as we shall see in treating the Beatitudes and the Sermon on the Mount.

Greed is excessive desire to get material things; it leads to setting one's heart on material things. Instead, St. Paul in First Corinthians 7:29-35 urges us to "hang loose", to be detached from material things, to not let them get a hold on us. This is the way to true happiness even in this life. Our Lord Himself (Luke 18:25) said, "It is easier for a camel to go through the eye of a needle than for a rich man to enter the Kingdom of God." Of course there is some Semitic exaggeration here, yet the solid truth is evident: riches are a great danger spiritually, unless there is true detachment — which is possible, as we see in the example of King St. Louis of France — but very difficult. The Gospel explanation of the parable of the sower says that the thorns stand for the riches and pleasures of this life, which can choke off the good seed (Matthew 13:22). 

Eighth Commandment: "You shall not bear false witness against your neighbor"

1. Telling the Truth

Human society can hardly operate if people do not tell the truth, for we are social beings, and need to be able to trust others. Truth telling is in a way a basis for love, for we cannot love what we do not know, or cannot trust. The Book of Proverbs (12:19) says: "Truthful lips endure forever, but a lying tongue does not last."

A lie is any action or statement, which when properly interpreted is known by the speaker to be false. The underlined words help us to see that the real meaning of a sentence comes not only from the meaning of each word taken alone, but from the whole context. For example, in Psalm 114:1, if we remove the context we find: "There is no God." But the words ahead of it: "The fool says in his heart" change the sense greatly. So if the mother sends the child to tell the salesman at the door that she is not home, the proper interpretation, which the salesman should know is: "Maybe she is here, maybe not. But if she is here, she does not want to see you." A statement issued by a nation at war should be understood to have no meaning. No one expects the government to give away its plans and capabilities.

Some authors prefer to speak of broad or a strict mental reservation. In both, one mentally limits the meaning of the words used. In strict reservation, no clue is given to what the speaker means; in broad reservation, such a clue is given. The strict mental reservation would be a lie, not the broad.

These things however should be used sparingly and with great prudence. Otherwise mistrust will come.

A lie normally is a venial sin. But a lie under oath, or a denial of the faith would be serious sin.

Hypocrisy is acting out a lie. Flattery is insincere praise of another in the hope of gaining something. Boasting is another form of deceit, in which the speaker claims to have fine qualities which he really lacks.

2. The Modern Media

They have great power of communication, and should be used honestly. If a news broadcast on TV shows Senator A, and lets him present his reasons fully, but merely mentions the reasons given by Senator B, there is a deceptive slanting. Unfortunately, this is not rare.

Advertising is normally exaggerated, and since we expect that a moderate exaggeration is not a lie. Yet it is unfortunate, for it makes it hard to know what is really true. Advertising is harmful when it entices people to spend beyond their means, or to be too attached to things of this world.

Some advertisers are ruthless, they employ commercials that create stress in the listener, to force attention to their product. This is at least against charity, for there is enough stress in the world without adding to it in this way.

3. Secrets

There are four levels of secrets, with the obligation increasing for each one: 

1)Natural secrets are things which by nature should not be revealed; they 
   deal with things someone would be reasonably unwilling to have known or 
   things that would be harmful to reputation. In this latter case, justice may 
   be involved, for people have a right to their reputation. 
2) Promised secrets are those that are made known first, and afterwards a 
   promise of secrecy is called for and given, 
3)Committed (entrusted) secrets are those that are revealed only after an 
   advance promise of secrecy. The promise may be explicit or implicit and 
   coming from the nature of the case, as in professional secrets. The 
   common good requires that these be kept. 
4)The seal of Confession is the most absolute secret of all. No reason 
   whatsoever can justify revelation.

With the first three kinds of secrets, a proportional reason can justify revelation for the public good, that of the civil society or the Church, or even the individual whose secret is revealed. As was said, each of the first three grow in strictness of obligation.

4. "Uncharitable speech"

This term covers three very different things: 

1)Slander means attributing a fault to another when it is not true. This is a violation of justice as well as truth, and demands that it be retracted. It is seriously sinful. 

2)Detraction consists in making known the true fault of another without proportionate reason. Here we need to consider both the reason, and how much damage is done — and we add that most people tend to underestimate the seriousness of this fault. We consider other factors too, for example if someone said he saw a sailor drunk, it would be much less than saying he say the Archbishop drunk. Then too, if the truth is soon to be made known anyway in the same place, little or no reason may be needed to speak of it. 

3)Uncharitable speech happens when two persons talk about the faults of another but no new information is given: both already know. 

Then we ask: is there some respectable reason for the talk? Rash judgment may be involved in any of the above things. The words of Christ "Judge not" (Matthew 7:1) do not prohibit reporting the objective fault of another, if there is sufficient reason, according to the rules just given. The command tells us to avoid saying we know the interior dispositions of the other person — which normally we cannot know. So to say someone has robbed a bank is not wrong, if true, and if there is sufficient reason for telling. For to rob a bank is objectively gravely wrong, no matter what the interior dispositions of the robber. But to say we would know the interior of the robbers — that would be wrong. Some false teachers confuse the two things, and even say, for example: "I cannot say that a homosexual act is wrong unless I know the dispositions of the one who indulges". We can and should say the homosexual act is gravely wrong; we should not claim to know the interior of the sinner.