This chapter deals with conditional kiddushin (קידושין על תנאי) and mistaken assumptions (טעות). The Rambam explains when a condition is considered essential and when a marriage is invalid because one side was misled.
Halachah 1-2: Mistaken Conditions Invalidate the Kiddushin
If a man says:
- “Be mekudeshet to me with this cup of wine,” and it turns out to be honey,
- “I am a Kohen,” and he is really a Levi,
- “I am rich,” and he is really poor,
- “My house is near the bathhouse,” and it is far,
or any similar case where the condition turns out false,
The kiddushin does not take effect.
Even if afterward either side says:
“In my heart I would have agreed anyway,”
the kiddushin is still invalid because:
דברים שבלב אינם דברים
Unexpressed thoughts do not have legal standing.
Halachah 3: When the Condition Is True Plus More
If he says:
“On condition that my name is Yosef,”
and his name is:
Yosef and Shimon,
the kiddushin is valid.
Likewise:
- He says he is a perfumer and he is both a perfumer and a tanner.
- He says he is a townsman and he owns residences in both town and city.
Since the stated condition is true, the extra information does not matter.
However, if he said:
“My name is only Yosef”
or
“I am only a townsman,”
and it turns out there is more than what he stated,
The kiddushin is invalid.
Halachah 4-6: Definitions of Learning and Status
The Rambam explains what various claims mean if a man uses them as conditions in kiddushin.
“I know how to read”
He must be able to read Torah and translate it into Targum Onkelos.
“I am learned” (קריינא)
He must know Torah, Nevi’im, and Ketuvim properly.
“I know Mishnah”
He must know Mishnah.
“I am a Tanna”
He must know Mishnah, Sifra, Sifrei, and Tosefta.
“I am a student”
Not Ben Azzai level.
Rather:
If you ask him a Torah question in his area and he can answer.
“I am a Chacham”
Not Rabbi Akiva.
Rather:
Someone who can answer questions of wisdom wherever he is asked.
“I Am Strong”
The Rambam says:
We don’t require the level of:
- Avner ben Ner
- Yoav
Rather:
A person whose peers are afraid of him because of his strength.
“I Am Rich”
Not the wealth of Rabbi Elazar ben Azaryah.
Rather:
Someone whom the people of his city honor because of his wealth.
“I Am a Tzaddik”
One of the most famous halachot in the chapter.
If he says:
“Be mekudeshet to me on condition that I am a tzaddik”
even if he is a complete rasha,
The kiddushin is safek kiddushin.
Why?
Because perhaps at that moment:
הרהר תשובה בלבו
He had a sincere thought of repentance.
“I Am a Rasha”
Conversely:
If he says:
“On condition that I am a rasha”
even if he is a complete tzaddik,
The kiddushin is also safek kiddushin.
Why?
Because perhaps he had a thought of idolatry.
The Rambam writes that even a thought of avodah zarah is so severe that it can render a person a rasha.
Final Halachah: Wrong Assumptions vs. Deception
The chapter ends with a very important distinction.
If a man says:
“I thought she was a Kohenet, but she is really a Leviyah,”
“I thought she was poor, but she is rich,”
the kiddushin remains valid.
Likewise if she mistakenly assumed things about him.
Why?
Because:
No one deceived anyone.
There was merely a mistaken assumption.
The whole chapter revolves around this distinction:
- False conditions or deception → kiddushin fails.
- Personal mistaken assumptions → kiddushin remains valid.
The Big Idea of Chapter 8
The chapter teaches that kiddushin depends on what was actually stated and agreed upon, not on hidden expectations.
What is spoken creates the agreement.
What remains only in the heart does not. (“דברים שבלב אינם דברים”)
That’s the unifying principle behind the entire chapter.