- המגרש את אשתו לא תנשא בשכונתו
It was taught in a Baraisa: המגרש את אשתו לא תנשא בשכונתו – If one divorces his wife, she should not remarry and live in his neighborhood. Rashi explains that since she recognizes his hints and gestures, she might come to sin with him. If her husband was a Kohen, לא תדור עמו במבוי – she may not dwell with him in a mavoi, even if she has not remarried, as Rashi explains, because a Kohen is prohibited to his divorcee. אם היה כפר קטן – If it was a small village in which they dwelt, this once occurred and the Chochomim said: כפר קטן נידון כשכונה – a small village is judged as a neighborhood. The Gemara asks: מי נדחי מפני מי – Who is displaced by whom? Must she leave the courtyard, or must he? The Gemara clarifies that if it is his courtyard, she is displaced, and if it is her courtyard, he is displaced. Therefore, the question is in a case that they each owned a home in the courtyard. The Gemara answers that she is displaced, for the passuk states: "מטלטלך טלטלה גבר" – Behold, Hashem will cause you to wander the wandering of a man, and Rav said that the reason the passuk refers to the wandering of a man is to teach, טלטולי דגברא קשין מדאיתתא – the wandering of a man is a greater hardship than the wandering of a woman.
- Testifying about one’s father’s, rebbe’s or brother’s handwriting that he saw as a child
The next Mishnah states: ואלו נאמנין להעיד בגודלן מה שראו בקוטנן – And these are trusted to testify during their adulthood regarding what they saw when they were minors, נאמן אדם לומר זה כתב ידו של אבא וזה כתב ידו של רבי וזה כתב ידו של אחי – This handwriting on the contract is the handwriting of my father, or of my Rebbe, or of my brother. The Gemara teaches that it was necessary for the Mishnah to mention all three cases. For if it had just mentioned his father’s handwriting, I might say it is because דשכיח גביה – he was frequently by him and came to know his handwriting. And if it had just mentioned his Rebbe’s handwriting, I might think it is because דאית ליה אמתיה דרביה – he was in awe of his Rebbe, and the mefarshim explain that he might have wanted to emulate it. And if it had only said the father or rebbe, then one might have thought he is not believed regarding his brother’s handwriting. Therefore, the Mishnah is coming to teach that since קיום שטרות מדרבנן – certification of a shtar is only a d’Rabbanon, the Rabbonon trust him regarding a d’Rabbanon.
- Testifying that one ate from a ketzitzah when he was a child
It was taught in a Baraisa: נאמן התינוק לומר...שאכלנו בקצצה של בת פלוני לפלוני – An adult is trusted to testify regarding what he saw as a child…that we ate from the ketzatzah distributed upon the marriage of the daughter of Ploni to Ploni. It was taught in another Baraisa: How is a ketzatzah done? If one of the brothers of a family marries a woman who is unfit for him, such as a mamzeres, באין בני משפחה ומביאין חבית מליאה פירות ושוברין אותה באמצע הרחבה – The members of his family come and bring a barrel full of fruit and break it in the middle of the town square and say: אחינו בית ישראל שמעו – "Our brothers, Beis Yisroel, listen! Our brother, Ploni, married a woman who is unfit for him, and we fear lest his seed become mixed with our seed," which is understood to mean that either their seed will mix with his, or that people will come to confuse their offspring with his offspring. "Come and take a דוגמא לדורות – a symbol for generations, so that his seed will not become mixed with our seed," and this is the ketzatzah that a child is trusted to testify about when he becomes an adult.