---
title: "Why does faithfulness in marriage and love matter?"
url: "https://seekabove.com/answers/what-is-the-sixth-commandment"
description: "The Sixth Commandment — “you shall not commit adultery” — protects the faithfulness and beauty of married love and, more broadly, calls everyone to chastity: ordering our sexuality toward genuine lov…"
published: "2026-06-06"
updated: "2026-06-06"
category: "Christian Life"
scripture: ["Exodus 20:14", "Matthew 5:27-28", "Matthew 19:6", "1 Corinthians 6:18-20", "Hosea 2:19-20"]
catechism: "CCC 2331, 2336–2337, 2364, 2380–2381, 2392, 2395"
---

# Why does faithfulness in marriage and love matter?

## Short answer

The Sixth Commandment — "you shall not commit adultery" — protects the faithfulness and
beauty of married love and, more broadly, calls everyone to chastity: ordering our
sexuality toward genuine love rather than using people. It forbids adultery and unfaithful
acts, while pointing positively to the goodness of self-giving, faithful love.

## Full explanation

At its most direct, this commandment guards **marriage**. Adultery — being sexually
unfaithful to one's spouse, or with someone else's — is a serious betrayal: it breaks a
solemn covenant, wounds a spouse and often children, and treats a sacred bond as
disposable. Jesus underscores how seriously God takes marital union: "what God has joined
together, let no one separate." Faithfulness isn't a quaint ideal; it's the very thing
that makes married love trustworthy and life-giving.

But Jesus, as with the other commandments, takes it deeper than outward acts. He teaches
that adultery begins in the heart: "everyone who looks at a woman with lust has already
committed adultery with her in his heart." So this commandment isn't only about a physical
act of betrayal; it's about the whole way we regard and treat other people — whether we see
them as persons to love or as objects to use.

That's why the Church understands the Sixth Commandment as the broad call to **chastity**
— the virtue that integrates our sexuality with real love, lived according to one's state
in life (married, single, or consecrated). Several specific questions flow from it, each
with its own fuller treatment: the meaning of chastity, the place of sex within marriage
(and so the teaching on sex before marriage and cohabitation), pornography, same-sex
attraction, and questions of marriage's nature. (See the dedicated entries on each.)

Underneath all the specifics is a positive vision the negatives are protecting:
sexuality is a *good* gift, powerfully tied to love and life, and the commandment exists
to keep that gift serving genuine self-gift rather than being hollowed out into use and
betrayal. God himself describes his covenant with his people in the language of a faithful
marriage — so faithfulness in love isn't an arbitrary rule; it reflects the very
character of God.

## Why this matters

Faithfulness is the soil real love grows in. Betrayal — in body or in heart — devastates
trust, families, and children, while the culture often treats sex as casual and commitment
as optional. The Sixth Commandment insists that people are worth fidelity and worth being
loved rather than used. Lived well, it protects marriages and trains every person, married
or not, to regard others as persons rather than objects.

## Common misunderstanding

One misunderstanding is that this commandment only forbids the physical act of adultery,
so lustful use of others "in the head" doesn't count. Jesus says otherwise — it begins in
the heart. The opposite misunderstanding hears the commandment (and the Church's sexual
teaching) as anti-sex; in fact it protects sex *because* it is good and meaningful, meant
for faithful, self-giving love.

## Scripture connections

- **Exodus 20:14** — "you shall not commit adultery," the commandment itself.
- **Matthew 5:27-28** — Jesus extends it to lust in the heart, not only the outward act.
- **Matthew 19:6** — "what God has joined together, let no one separate," the seriousness
  of marital union.
- **1 Corinthians 6:18-20** — "flee from sexual immorality"; the body as a temple of the
  Holy Spirit.
- **Hosea 2:19-20** — God's faithful, "married" love for his people, the model of fidelity.

## Church teaching references

- CCC 2331, 2336, 2337, 2364, 2380, 2381, 2392, 2395
- The Catechism treats the Sixth Commandment as the protection of marital fidelity and the
  call to chastity, with detailed teaching on sexuality.

## Reflection question

Beyond avoiding outright betrayal, where might you be treating someone as an object to be
used rather than a person to be loved — and what would faithful, self-giving love ask of
you instead?