We are up to Tractate Sanhedrin, chapter 7, Mishnah 9. The Mishnah continues to detail and explain the prohibitions listed earlier in Mishnah 4, the punishment for which is stoning. Here we have the law of one who cohabits with a betrothed young woman. Usually, the punishment for one who cohabits with a married woman is strangulation, but the Torah established a special punishment of stoning specifically for one who cohabits with a betrothed young woman.
The Mishnah states that for the punishment of stoning to apply, this young woman must meet four conditions: "Habba al na'arah hame'orasah - eino chayav ad shetehei na'arah, besulah, me'orasah, vehia beveis aviha" - one who cohabits with a betrothed young woman is not liable unless she is a young woman, a virgin, betrothed, and she is in her father's house. "Is not liable" - meaning he is not liable specifically to stoning, as opposed to strangulation. We will explain the four conditions in order.
The first condition - "na'arah":
There are three stages in the life cycle of a Jewish woman:
Ketanah: Her first twelve years.
Na'arah: Upon reaching the age of bas mitzvah, she transitions from the status of a ketanah to the status of a na'arah, provided two conditions are met: she has turned twelve, and she has begun the maturation process, which is measured by the appearance of two hairs. This period lasts exactly six months.
Bogeres: At the end of the six months, she becomes a bogeres from every halachic perspective, similar to a boy who becomes bar mitzvah.
Our Mishnah specifically uses the term "na'arah", and the Gemara learns from this that it refers only to a specific window of time: from age twelve and for the six months that follow, meaning between the ages of twelve and twelve and a half. The basis for this is in the verse, which explicitly states that she is a na'arah. The Sages, who are not mentioned here but whose opinion is accepted as the halachah, understand that the intention is a na'arah or a ketanah - a ketanah all the more so - so that at any stage up to the age of twelve and a half, the special punishment applies.
The reason our Tanna, Rabbi Meir, does not learn this way is because another verse teaches that in this case, and in any case of adultery, the punishment applies to both of them - to him and to her - assuming she consented and was not forcibly raped. But if it involves a ketanah, a girl who has not yet reached twelve years of age, a court can never punish her, and there is no way to impose a punishment on her under any circumstance. Therefore, Rabbi Meir understands that this law does not apply to her, and the term "na'arah" in the verse, which carries the special punishment of stoning that applies to both of them, was stated only when both of them are subject to punishment. Therefore, it is required that both he and she be adults, and if she is under the age of twelve - the law does not apply.
In halachah, therefore, the law applies up to the age of twelve and a half, and this includes even one who is under the age of twelve, provided that she is over the age of three.
The second condition - "besulah":
She must be a virgin, meaning she has never cohabited with another man and her virginity is intact.
The third condition - "me'orasah":
She must be married from a halachic perspective, but not married in practice. The practical stage is called nisuin, whereas being married from a halachic perspective means that she was betrothed with money or a document: someone gave her a ring and said, "Behold, you are betrothed to me with this ring", and she accepted the ring. With this, she became a married woman in every respect, and one who cohabits with her violates the prohibition of a married woman. Thus, we are dealing with a young woman who is a virgin, who has not been married previously, who is under the age of twelve and a half, and who is already married from a halachic perspective even though she does not yet live with her husband.
The fourth condition - "Vehi beveis aviha" - and she is in her father's house:
She must still be in her father's house. While this is generally the situation of a betrothed woman, the verse specifically states: "for she has done a disgraceful thing in Israel, to play the harlot in her father's house" - meaning she committed the act while still in her father's house. The verse comes to teach us about a case where the intended husband sent for her and dispatched his escorts, and he lives far away, such that she must be escorted from her father's house in the Land of Israel all the way to his location. From the moment she leaves her father's house and is on her way to him, even though she is not yet considered fully married since she has not yet moved in with her husband, she has already left her father's house. Therefore, if a man cohabits with her on the road between her father's house and the husband's location, he is liable to the death penalty of strangulation and not stoning, since she is no longer in her father's house.
To conclude, the Mishnah notes an interesting point: "Ba'u aleha shenayim, harishon besekilah vehasheni bechenek" - if two men had relations with her, the first is punished with stoning and the second with strangulation. The first is punished with stoning, as he cohabited with her while she was a virgin who had not been with any man before him; whereas the second is punished with strangulation, since she is no longer a virgin, after another man preceded him.
In summary: We learned that the special liability of stoning for one who has relations with a na'arah me'orasah is contingent upon four conditions - that she be a na'arah, a virgin, betrothed, and in her father's house. We discussed the stages of a woman's life and the dispute between Rabbi Meir and the Sages regarding the definition of a "na'arah", the distinction between erusin (betrothal) and nisuin (marriage), the significance of her remaining in her father's house, and the law when two men had relations with her - where the first is punished with stoning and the second with strangulation.