“Cursed"

Deuteronomy 27:22 - "Cursed be he that lieth with his sister, the daughter of his father, or the daughter of his mother. And all the people shall say, Amen."

Cain was married to either his sister or his niece. Sarah was Abraham's half-sister. Abraham's brother Nahor married his niece Milcah. Why was incest allowed in the Bible?

The Bible mentions a number of sexual relationships between close kin, most of which relate to the pre-Sinai period, before the handing down of the Mosaic law.

The first chapters of Scripture reveal a God who made sexuality core to the human experience—and indeed, the way that Adam and Eve would “fill the earth and subdue it.” Song of Solomon celebrates the sexual delight of lovers, while Paul taught that marital union represents the relationship between Christ and his church.

Because of this, Christianity remains among the most “sex-positive” religions, even if segments of the church have on one hand, cloaked it in shame or, on the other, given it a mystical power bordering on idolatry. Today’s Christians face a culture that, through pornography, media, and advertising, idolizes sexual pleasure while debasing its unitive and procreative power by extracting it out of relationship.

In this context, evangelicals struggle to teach and live out a biblical theology of sex that centers on the marital covenant between husband and wife, affirms the playful, non-procreative dimensions of sex, and welcomes the possibility of new life, even without a central teaching on birth control.

In the book of Deuteronomy, it is stated: “Cursed is anyone who sleeps with his sister, the daughter of his father or the daughter of his mother.” The people respond with an emphatic "Amen!". This prohibition reflects a cultural and moral norm against incestuous relationships.

Incest in the Bible refers to sexual relations between certain close kinship relationships which are prohibited by the Hebrew Bible. These prohibitions are found predominantly in Leviticus 18:7–18 and 20:11–21, but also in Deuteronomy.

In ancient times, tribal nations preferred endogamous marriage – marriage to one's relatives; the ideal marriage was usually that to a cousin, and it was often forbidden for an eldest daughter to even marry outside the family.

Marriage to a half-sister, for example, is considered incest by most nations today, but was common behaviour for Egyptian pharaohs; similarly, the Book of Genesis portrays Sarah as marrying Abraham, her half-brother, without criticising the close genetic relationship between them , and the Book of Samuel treats the marriage of a royal prince to his half-sister as unusual, rather than wicked.

Leviticus 18:7–11 and 20:11–21 sets out lists of prohibited relationships, and two chapters later specifies punishments for such unions, but the second list of unions is much shorter than the first. Critical scholars regard the lists as having originally been independent documents, bound together at a later point.

The Deuteronomic Code gives a yet more simple list of prohibited relationships – a man's parent's daughter (including his sister), a man's father's wife (including his mother), and a man's mother-in-law . In the Hebrew Bible, sexual relationships between siblings are forbidden to Jews , nonpermissible to Gentiles (non-Jews).

In the Bible, incest refers to sexual relations between close kinship relationships that are prohibited by the Hebrew Bible. These prohibitions are primarily found in Leviticus 18:7–18 and 20:11–21, as well as in Deuteronomy. Let’s explore some instances.

The relationships prohibited by Leviticus 18 are:

One's mother (Leviticus 18:7).

One's father (Leviticus 18:7).

One's stepmother (Leviticus 18:8).

One's paternal or maternal sister (Leviticus 18:9).

One's paternal sister through one's father's wife (Leviticus 18:11).

One's daughter (inferred from Leviticus 18:10).

One's granddaughter (Leviticus 18:10).

A woman and her daughter (Leviticus 18:17).

A woman and her granddaughter (Leviticus 18:17).

One's aunt by blood (Leviticus 18:12–13).

One's father's brother (uncle) (Leviticus 18:14).

One's father's brother's wife (aunt) (Leviticus 18:14).

One's daughter-in-law (Leviticus 18:15).

The Bible’s stance on incest reflects cultural norms and historical context, and it varies across different periods and narratives.

The Bible doesn't say, but we can speculate. First, there was an obvious need for marriage between close relatives, as the number of human beings on the earth at that time was limited. Adam and Eve’s children married their close relatives, by necessity, without it being considered incest.

But, even in those days, marriage between parent and child seems to have been disallowed: “That is why a man leaves his father and mother and is united to his wife, and they become one flesh” (Genesis 2:24).

Also, Adam and Eve were created genetically pure. They had no congenital defects to pass on to their offspring. DNA damage accumulates over time, but even 2000 years later, when Abraham was born, genes were healthy enough to allow for him to marry his half-sister. Genetic abnormalities did not influence marriage partners until the mutations were common enough to be a health risk.

Another possible reason is the patriarchy and tribalism common at the time. When Isaac needed a wife, Abraham did not want him to marry one of the local Canaanite women, whose religion was anathema to the worship of God.

So he sent his servant back to his homeland to find a woman from his relatives (Genesis 24). Later, Rebekah convinced Isaac to send their son Jacob away to her family to find a wife (Genesis 27:46). In doing so, the family unit was kept strong, and ungodly religious influences were kept to a minimum.

This was particularly true among Egyptian royalty, where incest was used to maintain the royal line—and make for some very unhealthy pharaohs.

God tightened incest standards when He gave the law to Moses. Leviticus 18:6 says, "None of you shall approach any one of his close relatives to uncover nakedness. I am the LORD." It goes on to elaborate: A man could not marry his mother, step-mother, sister (half or full, brought up within his family or in another home), granddaughter, step-sister (brought up as his sister), paternal or maternal aunt, father's brothers' wife, daughter-in-law, sister-in-law, or both a woman and her daughter or granddaughter, nor sisters while both are alive.

It is thought that there was no mention of a man marrying his daughter because the disgrace of the relationship was obvious. Notice how these laws maintain honor and peace within the larger family unit (Leviticus 18:6–18), and they also establish a morality still applicable today.

In ancient times, it was often taboo to have relations with your child or sibling, but the first comprehensive mandate against marriage among family members in the Bible didn't arrive until the Mosaic Law.