What does μοιχεία (moicheía) mean in the Bible?
moicheia means adultery, marital unfaithfulness, or covenant-breaking sexual betrayal. The direct New Testament witnesses are few but weighty.
Greek · G3430
μοιχεία
Adultery
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μοιχεία G3430
Pronunciation moicheía
What does μοιχεία (moicheía) mean in the Bible?
moicheia means adultery, marital unfaithfulness, or covenant-breaking sexual betrayal. The direct New Testament witnesses are few but weighty.
Reader summary
Full entry for μοιχεία (G3430) · Open the biblical lexicon
Questions this entry answers
How does the BSB render G3430?
The BSB source-word alignment has 3 aligned rows for this entry. Common renderings include adultery (3).
Where does μοιχεία (moicheía) appear in Scripture?
The source-word alignment first shows this entry at Matthew 15:19. Its strongest book concentrations include John (1), Mark (1), Matthew (1).
What This Word Actually Means
Moicheia means adultery, marital unfaithfulness, or covenant-breaking sexual betrayal. The direct New Testament witnesses are few but weighty. Jesus lists adulteries among the evils that come from the heart and defile a person in Matthew and Mark, and John records a woman brought before Jesus as having been caught in adultery. The word must not be used as a blunt instrument.
It names real sin against God, spouse, neighbor, and covenant, yet the Gospel scenes also warn against hypocritical accusation and self-righteous spectacle. Pastorally, moicheia should be preached with moral clarity, protection for the sinned-against, honest repentance for sinners, and confidence that Jesus exposes hearts while extending mercy that calls people away from sin.
How the Bible Uses It
Moicheia appears in three direct New Testament witnesses. Matthew and Mark place adultery among evils arising from the heart, while John 8 places adultery inside a public accusation scene before Jesus.
- Matt.15.19
For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false testimony, and slander.
Jesus says adultery comes from the heart. moicheia is not merely an external act but part of inner defilement.
- Mark.7.21
For from within the hearts of men come evil thoughts, sexual immorality, theft, murder, adultery,
Mark's parallel places adultery among evils that proceed from within. The word belongs to Jesus' diagnosis of defilement.
- John.8.3
The scribes and Pharisees, however, brought to Him a woman caught in adultery. They made her stand before them
John's scene presents adultery amid public accusation before Jesus. The context warns against both minimizing sin and weaponizing shame.
Old Testament background
In the LXX, μοιχεία and its cognates render the Hebrew root נָאַף (na'ap), the word used in the seventh commandment (Exod 20:14; Deut 5:18) and throughout the prophets for Israel's spiritual adultery against God. This OT background means that when Jesus uses the word in his vice lists, his hearers would hear both the marital and the covenantal register simultaneously.
Source Word Evidence
BSB source-word alignment connects this entry to exact verse rows, English rendering, source form, transliteration, and parsing.
How English Renders It adultery 3× Matthew 15:19, Mark 7:21, John 8:3
Show sample aligned rows
Usage map
A compact distribution from source-word alignment before the full evidence tables.
First aligned row Matthew 15:19
Aligned rows 3
Books represented 3
Matthew 1 Mark 1 John 1
Source forms
μοιχεῖαι 2x moicheiai Matthew 15:19, Mark 7:21
μοιχείᾳ 1x moicheia John 8:3
Parsing patterns
Noun - Nominative Feminine Plural 2x Matthew 15:19, Mark 7:21
Noun - Dative Feminine Singular 1x John 8:3
Using This Word Well
Be careful not to...
- Confess sexual sin truthfully while seeking protection, repentance, and wise pastoral care.
- Do not use another person's adultery as a way to avoid your own heart before Jesus.
Avoid claiming...
- Do not claim moicheia is the only sexual sin named in the New Testament.
- Do not claim Jesus minimizes adultery when He confronts hypocritical accusers.
Evidence Summary
Greek word. Sexual unfaithfulness within marriage; distinct from fornication as violation of marriage covenant specifically.
Strong's G3430
Lexical occurrences 2 verses Greek text appearances 4 times Word forms 1 form 2 references Verse guides 0 guides
Study link Jeremiah 5:7-9 Source Gloss
adultery
Extended definition Source: STEPBible TBESG + Abbott-Smith
Sexual unfaithfulness within marriage; distinct from fornication as violation of marriage covenant specifically.
(μοιχύω), [rn LXX: Hos.2:2 (נַאֲפוּף), Hos.4:2 (נָאַף), Jer.13:27 (נִאֻף), Wis.14:26 * ;] adultery: Jhn.8:3; pl. (see WM, 220; Bl., § 32, 6), Mat.15:19, Mrk.7:21,
Greek Text Appearances
Textus Receptus witness, full corpus Greek token appearances from Scrivener 1894 Textus Receptus in the full New Testament corpus.
4 Greek text appearances shown. Linked morphology labels have verse guides.
Matthew 15:19 Noun Nominative Plural Feminine
μοιχεῖαι, moiceiai
adultery
Read verse Mark 7:21 Noun Nominative Plural Feminine
μοιχεῖαι, moiceiai
adultery
Read verse John 8:3 Noun Dative Singular Feminine
μοιχείᾳ moiceia
adultery
Read verse Galatians 5:19 Noun Nominative Singular Feminine
μοιχεία, moiceia
adultery
Read verseFull New Testament corpus: 260 chapters, 7,957 verses, 140,628 tokens. Data source: honza/textus-receptus (data only), with authority check against byztxt/greektext-textus-receptus.
Grammatical Forms
How this word appears across different grammatical cases and numbers.
This word appears as a noun across 1 case and number pattern. The form changes show how the word functions in a sentence; they do not change the basic lexical meaning by themselves.
Form patterns 1 Aligned forms 2 Case pattern Nominative (2) Number pattern Plural (2)
Verse guides are not available for this word yet, so verse references remain plain evidence markers.
Nominative · Plural · Feminine Matt 15:19 · Mark 7:22 2×
Sampled Scripture Occurrences
Representative Scripture witnesses for this entry: passage, original form, and sense in context.
Biblical Witnesses
Violation of marital covenant, condemned as rebellion against God
Spiritual unfaithfulness of prophets alongside literal marital infidelity
Physical infidelity as moral corruption warranting divine judgment
Illicit sexual relations bringing shame, jealousy, and irreversible consequences
Word Origins
μοιχεία is built from this root:
Part of These Phrases
Compound and idiomatic phrases that include this word. Follow a link to study the phrase and how its parts work together.
For the Preacher and Teacher
Moicheia is a severe word because adultery tears at covenant, body, trust, family, and worship. Jesus' lists in Matthew and Mark prevent any clean division between outward act and inward heart: adulteries come from within and defile. John 8 adds a public scene where a real charge is turned into a trap and spectacle. Jesus neither blesses adultery nor joins the accusers' self-righteous cruelty.
He exposes hearts and calls the woman away from sin. The preacher must therefore reject both permissiveness and weaponized shame. This word should lead to repentance, protection for betrayed spouses, restoration where truly possible, and humble reliance on the mercy and holiness of Christ.
Anchor passage
Matt.15.19
Doctrinal connections
- Heart defilement: Matthew 15:19 says adultery proceeds from the heart.
- Moral seriousness: Mark 7:21 places adultery among evils that defile people before God.
- Covenant faithfulness: the word assumes the moral weight of marriage vows before the Lord.
- Hypocrisy exposed: John 8 shows accusers using adultery as a public trap before Jesus.
- Mercy and holiness: John 8 refuses both condemnation games and permission to continue in sin.
- Christ's authority: all selected witnesses place sexual ethics under Jesus' diagnosis and judgment.
Moicheia is the noun adultery. It is related to other adultery-family terms but should not be merged with every sexual-ethics term without attention to the exact word and passage.
From Old to New Testament
The command against adultery, prophetic warnings about covenant betrayal, and wisdom's cautions about desire all stand behind the New Testament's continued seriousness about moicheia.
Sources
MorphGNT Strong's Dictionary XML — CC0 1.0 Public Domain
Open Scriptures Hebrew Bible (morphhb/OSHB) — CC BY 4.0
Open Scriptures Hebrew Lexicon — CC BY 4.0
Berean Standard Bible (BSB) source-word alignment - CC0 Public Domain