Chapter Overview
The Rambam opens Sefer Nashim (The Book of Women) by defining the Torah’s framework for marriage. He explains:
- How marriage functioned before Matan Torah.
- The institution of kiddushin.
- The prohibition of casual relations.
- Categories of forbidden relationships.
- Rabbinic safeguards around marriage.
This chapter lays the groundwork for all later laws of marriage and family.
The Four Mitzvot of Hilchot Ishut
The Rambam begins by listing four mitzvot:
Positive Commandments
- To marry through kiddushin and ketubah.
- To be fruitful and multiply.
Negative Commandments
- Not to conduct a marital relationship without kiddushin and ketubah.
- Not to withhold food, clothing, and marital obligations from one’s wife.
Halachah 1 – Marriage Before and After Sinai
Before the Torah was given:
- A man and woman who wished to marry simply lived together.
- No formal legal procedure was required.
After Matan Torah:
- Marriage requires a formal acquisition (kiddushin).
- It must take place before witnesses.
- Only afterward may they live together as husband and wife.
This is derived from:
“When a man takes a woman and comes to her.”
The “taking” must precede the relationship.
Halachah 2 – Kiddushin
Kiddushin is a Torah commandment.
A woman may become betrothed through:
- Money (Kesef)
- A document (Shtar)
- Marital relations (Bi’ah)
These legal acts create the status of mekudeshet (betrothed).
The terms:
- Kiddushin
- Erusin
are used interchangeably by the Rambam.
Halachah 3 – The Power of Kiddushin
Once kiddushin takes effect:
- The woman is already considered a married woman (eshet ish).
- Even though she has not yet entered her husband’s home.
- Even though the marriage has not yet been consummated.
Any other man who has relations with her is treated as violating the prohibition of adultery.
If separation is desired, a valid get is required.
Halachah 4 – The Prohibition of Casual Relations
Before the Torah, casual consensual relations were permitted.
After Matan Torah, this became forbidden.
The Torah states:
“There shall not be a kedeshah among the daughters of Israel.”
Therefore, according to the Rambam:
Any sexual relationship conducted without kiddushin and marriage falls under this prohibition.
This is one of the Rambam’s famous and sometimes debated positions.
Halachah 5 – Arayot (Biblically Forbidden Relationships)
The Rambam defines arayot as those relationships prohibited by the Torah and punishable by karet.
Examples include:
- Mother
- Sister
- Daughter
- Other close relatives
Each such prohibited relative is called an ervah.
Halachah 6 – Shniyot (Rabbinic Secondary Prohibitions)
Beyond Biblical prohibitions, the Sages added protective restrictions called shniyot (“secondary relatives”).
These create additional distance from the Torah prohibitions.
The Rambam lists twenty such relationships.
Four Shniyot Without Limit
Most shniyot stop after a certain generation.
Four continue indefinitely upward or downward:
Upward
- Mother’s mother and all her ancestors
- Father’s mother and all her ancestors
- Wife of paternal grandfather and all earlier generations
Downward
- Descendants of a son’s wife
These remain prohibited generation after generation.
Halachah 7 – Issurei Lavin
The Rambam next discusses relationships prohibited by ordinary negative commandments rather than by karet.
Examples include:
Kohanic Restrictions
- Widow to a Kohen Gadol
- Divorcee to a Kohen
National Restrictions
- Mamzer marrying into the Jewish people
- Certain prohibited lineages entering the congregation
Other Cases
- A divorced woman who remarried another man and then seeks to return to her first husband
- Certain yibbum-related prohibitions
These are termed:
Issurei Lavin
and also
Issurei Kedushah
Halachah 8 – Positive-Prohibition Relationships
Some relationships are prohibited by implication from a positive commandment rather than from an explicit prohibition.
Examples:
Egyptian and Edomite Converts
First and second generations may not marry into the congregation.
A Non-Virgin and the Kohen Gadol
The Torah commands the Kohen Gadol:
“A woman in her virginity shall he take.”
From this positive requirement we infer the prohibition.
The Rambam notes:
A prohibition derived from a positive commandment has the legal status of a positive commandment.
Key Concepts Introduced in This Chapter
| Concept | Meaning |
| Kiddushin | Formal legal betrothal |
| Erusin | Another name for Kiddushin |
| Eshet Ish | A legally married woman |
| Kedeshah | Prohibited casual sexual relationship |
| Arayot | Biblically forbidden relatives |
| Shniyot | Rabbinic secondary prohibitions |
| Issurei Lavin | Relationships prohibited by a negative commandment |
| Issurei Kedushah | Another category name for certain marriage prohibitions |