1 Corinthians 6:18

“Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body.”

1 Thessalonians 4:3–5

“For this is the will of God, even your sanctification, that ye should abstain from fornication…”

Acts 15:20 - Council at Jerusalem

“…that they abstain from pollutions of idols, and from fornication…”

Catechism of the Catholic Church: 2353 Fornication is carnal union between an unmarried man and an unmarried woman. It is gravely contrary to the dignity of persons and of human sexuality which is naturally ordered to the good of spouses and the generation and education of children. Moreover, it is a grave scandal when there is corruption of the young.

Paul teaches that the body is a temple of the Holy Spirit, so sexual sin uniquely harms one's own body (1 Corinthians 6:15–20).

“Do you not know that he who unites himself with a prostitute is one with her in body? For it is said, “The two will become one flesh.” 1 Corinthians 6:16

Marriage is presented as the solution to sexual temptation (1 Corinthians 7:2–9).

Sex mirrors divine covenant faithfulness (God & Israel/Church); violating it is like spiritual unfaithfulness/idolatry.

Rules aim to protect women/children from exploitation, reduce jealousy/violence, and channel sexuality into stable, procreative unions.

Rules against fornication (sexual intercourse outside of marriage) consider it a serious moral and spiritual sin. This opposition is based on sex as something sacred, tied to marriage (understood as a covenant between man, woman, and God), family stability, lineage clarity, personal holiness, and obedience to divine commands.

Sex outside marriage (whether premarital/fornication or extramarital/adultery) is seen as:

• A rebellion against God's design for human relationships (starting from Genesis: "a man shall leave his father and mother and be joined to his wife, and they shall become one flesh") Genesis 2:24

• Harmful to individuals (spiritually polluting the body/temple, creating guilt/shame, addictive potential).

• Damaging to society (complicating paternity, weakening family units, spreading moral decay, rivaling idolatry in severity).

• Often ranked among the gravest sins after idolatry and murder.

This creates a unified "fence" around sexuality: sex is powerful and God-given. It must be channeled exclusively into lifelong heterosexual marriage. Anything else is forbidden (often called "sexual immorality" in broad terms).

no sex outside of marriage

not for any reason, because we cannot do evil to do good - even if we lose someone

and sex can wait until we either choose our vocation or get married

christians should get used to resisting pressure and valuing our relationship with God more than other people, even those we love (and being prepared to lose them for a higher love & purpose)

"And why not do evil that good may come?—as some people slanderously charge us with saying. Their condemnation is just." (Romans 3:8, RSV-CE or similar translations; often rendered as "Let us do evil that good may come," with Paul rejecting the notion.)

Catechism of the Catholic Church:

1755 A morally good act requires the goodness of the object, of the end, and of the circumstances together. An evil end corrupts the action, even if the object is good in itself (such as praying and fasting "in order to be seen by men").

The object of the choice can by itself vitiate an act in its entirety. There are some concrete acts - such as fornication - that it is always wrong to choose, because choosing them entails a disorder of the will, that is, a moral evil.

1756 It is therefore an error to judge the morality of human acts by considering only the intention that inspires them or the circumstances (environment, social pressure, duress or emergency, etc.) which supply their context. There are acts which, in and of themselves, independently of circumstances and intentions, are always gravely illicit by reason of their object; such as blasphemy and perjury, murder and adultery. One may not do evil so that good may result from it. Romans 12:21
“Do not be overcome by evil, but overcome evil with good.”

Romans 3:8: Why not say—as some slanderously claim that we say—"Let us do evil that good may result"? Their condemnation is just!

Aquinas identifies the primary end of sex as stable unions. Pleasure accompanies the act to encourage it, but the act must be ordered toward this end.

• Sexual intercourse is naturally directed toward stability and procreation

Why Fornication Violates This:

In fornication:

• There is no stable, permanent union (marriage)

• The act becomes ordered primarily toward pleasure rather than the natural end of a well-ordered society

In the Summa Contra Gentiles (Book III, Chapter 122), he emphasizes that irregular sexual unions outside marriage are contrary to the good of the species and human flourishing:

Marriage is natural to man, and an irregular connexion outside of marriage is contrary to the good of man; and therefore fornication must be sinful.

In Summa Theologica II-II, q. 154, a. 2, he defends that simple fornication is a mortal sin (grave matter)

Pope John Paul II - Splendour of Truth “Consequently, as the Catechism of the Catholic Church teaches, "there are certain specific kinds of behaviour that are always wrong to choose, because choosing them involves a disorder of the will, that is, a moral evil".127 And Saint Thomas observes that "it often happens that man acts with a good intention, but without spiritual gain, because he lacks a good will. Let us say that someone robs in order to feed the poor: in this case, even though the intention is good, the uprightness of the will is lacking. Consequently, no evil done with a good intention can be excused. 'There are those who say: And why not do evil that good may come? Their condemnation is just' (Rom 3:8)".128”

“1 Timothy 5:2 - 1Do not rebuke an older man, but appeal to him as to a father. Treat younger men as brothers, 2older women as mothers, and younger women as sisters, with absolute purity.”

The Christian Rules of Society require politeness and respect. Relations between men and women should be spiritualized with purity. Society itself can place immense pressure on people to commit to relationships or fornication. People may feel that they are being forced or pressured. Maybe they are warned of social consequences if they don’t “get with it”. Christians are different -

1 Corinthians 7:7–8

“I wish that all of you were as I am [unmarried]. But each of you has your own gift from God…
To the unmarried and the widows I say that it is good for them to stay unmarried, as I do.”

1 Corinthians 7:37–38

“Nevertheless he that standeth stedfast in his heart, having no necessity, but hath power over his own will, and hath so decreed in his heart that he will keep his virgin, doeth well.
So then he that giveth her in marriage doeth well; but he that giveth her not in marriage doeth better.”

In matters of the opposite sex, one can remain polite, respectful and with purity without compromising one’s values. A person’s vocation is to be discerned. Friendship with the opposite sex varies from culture to culture. Deep emotional attachment without maturity or appropriate circumstances may result in poor decision-making. Essentially, we are called to avoid the occasions of sin. If someone, or something, would endanger our souls we should avoid them. There should be no causing of offense to the other person (if it can be avoided) who may very well be unaware. We should be careful not to hurt feelings. Nevertheless, we should do what is best for God and avoid sin. Surely, that would bring blessings upon ourselves for our object of emotion.

Sublimation is a process whereby forbidden thoughts and emotions are channeled into productive and often creative ends. Even if someone (who themselves might be good) might not be good for us, we can still appreciate their creative and spiritual talents in other ways.

Now it can feel like separation can cause anxiety, love-sickness, or an emptiness that is difficult to fill. This can cause a real soul sickness. However, the virtue of fortitude allows us to overcome difficulties and obstacles. Love is often complimentary. What we lack ourselves, we often find in another person. It can feel like it completes the puzzle. Unfortunately, this can be fantasy and illusory as well. We might be making deeper emotional problems for ourselves. Therefore, we should strive for purity and uprightness.

When we end friendships it is not because we hate the other person, or we are cowards - it is simply because we love God and the soul of the other person more, and their eternality, without causing ourselves or the other person to sin. It is not to say in different circumstances, we could be friends again, but at this stage the Spirit is leading us in other directions, although still filled with the Love that is Care & Charity even if it is not close and romantic - those last two being the emotions that would affect our relationship with God and the care we have for the soul of the other person that we always prioritize over physical longing for them.

Even if we should feel the sky would fall unless we permitted a sinful act, we still must not do it -

"The Catholic Church holds it better for the sun and moon to drop from heaven, for the earth to fail, and for all the many millions on it to die of starvation in extremest agony, as far as temporal affliction goes, than that one soul, I will not say, should be lost, but should commit one single venial sin, should tell one wilful untruth, or should steal one poor farthing without excuse.” Cardinal Newman

“Romans 12:12 - Be joyful in hope, patient in affliction, faithful in prayer.”

“1 Corinthians 4:10 - We are fools for Christ, but you are wise in Christ. We are weak, but you are strong. You are honored, but we are dishonored.”

Augustine wrote of different types of loves. One caritas is properly ordered towards God, the other cupiditas is disordered. Cartias is a caring love directed towards God and others properly. Cupiditas is selfish love that contrasts with caritas (divine or selfless love). For Augustine, only God may be properly enjoyed (frui). Uti means to use something as a means toward another end. Created things—including other people—are to be used in the sense that they help lead us toward God.

Caritas = frui (enjoy) God, uti everything else in reference to God. Cupiditas = frui (enjoy) created things (or oneself), thereby displacing God. Frui is loving and resting in God as your ultimate end, while uti is loving all created things only insofar as they lead you to God.

The birdcage analogy can be used with love. If we truly love someone we want them to be free and let them go. Someone with an obsessive, fanatical love of someone does not really love them. They only want to control them. That is not real love. It is not mutual love - it is all one sided.To clip a bird’s wings and keep it in a cage is a sign of possession not love. If you love something, sometimes you need to let them go. This is not failure, but a mature and loving assessment of the situation.

The other issue is jealousy. James 3:16 “For wherever there is jealousy and selfish ambition, there you will find disorder and evil of every kind. But the wisdom from above is first of all pure. It is also peace loving, gentle at all times, and willing to yield to others. It is full of mercy and the fruit of good deeds. It shows no favoritism and is always sincere.”

The word for jealous in Greek is ζῆλος (zēlos) which basically means: an intense inner heat that refuses to be indifferent. If zeal is protecting God’s honor it produces humility and peace. But if it is your status, control, or identity then it turns bitter. That “heat” can go in two directions: Positive passion, devotion, commitment (zeal), Negative: resentment, rivalry, possessiveness (jealousy/envy). Which is why we should not be possessive or jealous of people and the decisions they make. It only produces an intense fire which is not for the Greater Glory of God, but for selfish ambition, self-love, ego and self-destruction. The answer is in Scripture - Blessed are the Meek, The Gentle, and Blessed are the Peacemakers (Sermon on the Mount).

Possessiveness is an intense, often unhealthy desire to control or dominate a person’s time, actions, and emotions, usually rooted in deep-seated insecurity and a fear of abandonment. It manifests as jealousy, monitoring behaviors, and a refusal to allow independence, often mistaken for love but driven by a need to prevent loss.

The antidote is contentment, purity of heart, gratitude for God's gifts, and pursuing holiness—trusting that God provides what is best and that marriage is sacred. Believers are called to guard their hearts (Proverbs 4:23), flee sexual immorality (1 Corinthians 6:18), and rejoice rather than envy (Romans 12:15). Thessalonians 5:18: "Give thanks in all circumstances"

Proverbs 14:30

“A tranquil heart gives life to the flesh, but envy makes the bones rot.”

Proverbs 27:4

“Wrath is cruel, anger is overwhelming, but who can stand before jealousy?”

Love vs jealousy

1 Corinthians 13:4

“Love is patient and kind; love does not envy.”

James 4:1–2

“What causes quarrels and what causes fights among you? Is it not this, that your passions are at war within you? You desire and do not have, so you murder. You covet and cannot obtain, so you fight and quarrel.”

James 3:14–16

“If you have bitter jealousy [zeal] and selfish ambition in your hearts… this wisdom is not from above. For where jealousy and selfish ambition exist, there will be disorder and every vile practice." It breeds chaos, evil actions, and community breakdown.