I don't understand Matthews 5:27


Fornication and adultery are not the same thing. Fornication is sexual relations between unmarried people. Adultery is a married person having sexual relations with a person who isn’t their spouse.

However, Matthews 5 27 implies that lust is adultery. It says that whoever is guilty of lust is also guilty of adultery. Doesn’t this imply that fornication is a form of adultery? If not, then what does that verse mean?


The 6th commandment speaks of adultery (you shall not commit adultery)…it though covers all forms of sins against chastity…lust, fornication etc.

Interior sins of lust (lusting after a woman) are also gravely wrong.

Indeed they fall under the 6th commandment.

Jesus is pointing to the reality that such interior sins are also gravely wrong…


Practically, either one can send one to to permanent hell. Despite the differences or similarities, best to avoid both, according to your Lord.

From the catechism:

Offenses against chastity


2351 Lust is disordered desire for or inordinate enjoyment of sexual pleasure. Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes.


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.



2380 Adultery refers to marital infidelity. When two partners, of whom at least one is married to another party, have sexual relations - even transient ones - they commit adultery. Christ condemns even adultery of mere desire.171 The sixth commandment and the New Testament forbid adultery absolutely.172 The prophets denounce the gravity of adultery; they see it as an image of the sin of idolatry.


Ok a bit of context helps here to understand the passage.

Jesus first says "You have heard that it was said to the ancients: ‘You shall not commit adultery.’ "
So He is speaking about a married man.

Then he states “But I say to you, that anyone who will have looked at a woman, so as to lust after her, has already committed adultery with her in his heart.”

So lusting about a woman and you are married is the same as actually commiting adultery.

Jesus is laying out a foundation on how we should act in our lives. If we apply it to the rest of the commandments then.
An unmarried man that lusted after a woman has commited fornication, a man lusting over another man’s property has committed stealing, etc.


Also - in the realm of context…In the culture of the time people were married off quite young so the opportunity to commit fornication was not as likely as committing adultery…

Just a thought…



How many times does “bible alone” have to disprove itself?


Fully agreed on all counts. The term “adultery” in the Commandment is a blanket term to cover all sexual sins (something that “gay rights” activists conveniently choose to ignore.) For a fuller exposition of what it implied to an Israelite trained in the Law, see Leviticus 18. Christ extended this law to include interior sins.


Many good answers.

Also - we need to understand Mt 5:27 in light of Mt 22:36-40.

All the law is summarized in loving God and neighbor.

It is easy to see that adultery is a hurtful thing. But so is fornication. It is not loving another as we love ourselves. Therefore it should not be done.



It’s important to read the whole chapter 5 for the context. The Beatitudes beautifully express Jesus’ point. Jesus is pointing us to radical conversion, not -merely- to a life of external observance to the law. This requires a remaking of the inner man, conforming us to the law of love in relationship to Jesus Christ. The source of sin is the inner man, our wills, our choices. If our own will is not in conformity with God’s will, observing the law does not save us. So it is not enough to claim righteousness because we refrained from sex with someone who is not our wife. If we lust, our will is unfaithful.

Also, consider that adultery can be used in the context of the God/man relationship. We are adulterous when our hearts and wills do not serve God. The scriptures refer many times to the fact that we stray from God. This is the worst sense of adultery of all.


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