μοιχεία

adultery

Definition

Μοιχεία specifically refers to the act of adultery, which in the biblical context is sexual infidelity by a married person. It denotes a violation of the marriage covenant, as established in the Old Testament law (Exodus 20:14). In the New Testament, Jesus expands this concept beyond the physical act to include lustful intent in the heart (Matthew 5:28), though the noun μοιχεία itself is used for the concrete sin. It appears in lists of vices that characterize a life opposed to God, such as in Galatians 5:19, where it is a 'work of the flesh.'

Biblical Usage

Μοιχεία is used exclusively in vice lists within the New Testament, highlighting it as a fundamental moral transgression. It appears in the Gospels in lists of sins that proceed from the human heart (Matthew 15:19, Mark 7:21). In John 8:3, it is the specific charge against the woman brought before Jesus. Its final occurrence is in Paul's list of the 'works of the flesh' in Galatians 5:19, categorizing it as behavior characteristic of an unregenerate life opposed to the Spirit.

Etymology

Derived from the verb μοιχεύω (moicheuō, G3431), meaning 'to commit adultery.' The root is connected to μοιχός (moichos), meaning 'an adulterer.' The word group carries the consistent sense of violating marital fidelity, a concept deeply embedded in both Greek and Hebrew moral thought.

Semantic Range

Μοιχεία is theologically significant as it represents a breach of covenant faithfulness, mirroring the language used for Israel's idolatry in the Old Testament (e.g., Jeremiah 3:8-9). It is presented not merely as a social crime but as a sin against God and a destructive 'work of the flesh' (Galatians 5:19) that excludes one from the kingdom. Understanding this Greek term reinforces the biblical view of marriage as a sacred covenant and underscores the seriousness with which God views purity in heart and action.

In the first-century Greco-Roman and Jewish worlds, adultery was understood as a man having sexual relations with another man's wife, violating the husband's property rights and social honor. For a married woman, any extramarital sex was adultery. Jesus' teaching challenged and deepened this understanding by focusing on the heart's condition and the equality of men and women under this moral law.

πορνεία (porneia, G4202) — a broader term for sexual immorality, including but not limited to adultery. μοιχεύω (moicheuō, G3431) — the verb 'to commit adultery.' μοιχός (moichos, G3432) — the noun 'adulterer' or 'adulteress.'

Word Details

Scripture References