Leviticus 18:13 forbids a man from having sexual relations with his mother’s sister, and the verse gives the reason in a single clause: she is his mother’s close relative, so the family bond itself is protected. God spoke these words through Moses to the people of Israel as they were preparing to enter the land of Canaan, and the instruction belongs to a longer section that sets boundaries around marriage and sexual conduct within the household.
“‘You shall not uncover the nakedness of your mother’s sister: for she is your mother’s near kinswoman.
Leviticus 18:13 (WEB)
What Leviticus 18:13 Means
The phrase “uncover the nakedness” is the Old Testament’s way of describing sexual relations. It does not refer to simple nudity. The command is therefore a prohibition against intercourse with a particular relative. The word “shall not” makes this a direct instruction rather than a suggestion, and it applies to the reader personally rather than to a general category of people.
The reason offered is brief but important. The woman is described as the mother’s “near kinswoman,” a term that places her inside the close family circle. Her relationship to the speaker is shaped by her relationship to his mother, so the verse protects the integrity of that family line and the trust that comes with it.
What the verse does not do is spell out every social consequence or lay out a full legal procedure. It states the boundary and its basis. Readers who expect a detailed case-by-case commentary will need to look to the wider Levitical law and to the traditions that interpreted it over many centuries.
The Context of Leviticus 18:13
Leviticus is the third book of the Torah, the first five books of the Bible, and tradition attributes its laws to Moses. Chapter 18 opens with a call for Israel to live differently from the nations around them, and it lists a series of forbidden unions that define holiness in the everyday life of the household. The audience is the whole covenant community, not only priests or leaders.
The verses just before and after show a deliberate pattern. Verses 10 through 16 move through a sequence of close relatives: a granddaughter, a half-sister, a father’s sister, the mother’s sister, an uncle’s wife, a daughter-in-law, and a brother’s wife. Each prohibition names a relationship, and the repeated phrase “it is your own nakedness” or “she is your near kinswoman” shows that these unions are forbidden because they breach the bonds of kinship. Read in that sequence, verse 13 is one link in a careful, consistent map of family boundaries.
Key Phrases in Leviticus 18:13
Leviticus 18:6
“‘None of you shall approach any close relatives, to uncover their nakedness: I am the LORD.
(WEB)
This verse sets the general principle that stands behind the whole chapter: no one may approach close blood relatives sexually. Reading it alongside verse 13 shows that the list of specific prohibitions grows from a single concern for the dignity and safety of family life.
Ephesians 5:3
But sexual immorality, and all uncleanness, or covetousness, let it not even be mentioned among you, as becomes saints…
(WEB)
Paul’s call to purity in the New Testament carries the same concern for sexual integrity into the life of the church. It helps readers see that the ethical vision of Leviticus continues to shape Christian thinking about how bodily intimacy honors God and others.
A Short Prayer From Leviticus 18:13
Lord, you made families as places of trust, care, and belonging. I ask you to help me honor those bonds with clear and faithful boundaries. Where my feelings or circumstances feel confusing, give me the wisdom to seek good counsel and the courage to act with integrity. Protect the people I love from harm, and guard my own heart from desires that would damage what you have joined together. Thank you for the clear guidance found in your word. Amen.
