Kesubos, Chapter Nine, Mishnah 4. This mishnah addresses the question of when a husband may impose an oath on his wife regarding monetary matters, and where the line falls between defined financial responsibility and excessive interference in the running of the home.
The first case - appointment to a financial role:
A man who appointed his wife during their marriage to serve as a "chenvanis" - that is, as the one in charge of the store, selling merchandise and the like - or who appointed her as an apotropos (guardian) over funds, has given her a financial role in his affairs. Since a significant position of monetary responsibility was placed in her hands, the husband may require her to swear at any time that she was careful with the money and did not take any of it for herself.
The view of Rabbi Eliezer:
Rabbi Eliezer holds that even if he never placed her in any financial position at all, every woman has "hatzemer she'hi tovah v'habatzek she'hi lashah" - the wool she spins and the dough she kneads, the ordinary tasks of running a household. In his view the husband may impose an oath on her even over so small a matter, which is part of the routine activity of the home, and demand that she swear she took nothing and set nothing aside for her own personal needs without his permission.
The view of the Tanna Kamma:
The Tanna Kamma disagrees and holds that this is not within his power, and he distinguishes between two situations:
An oath on its own: The husband may not impose an oath on his wife regarding household expenses alone, in order to verify that she is handling the household expenses properly. That is too demanding a stance and too domineering a relationship, and he is not permitted to act that way.
By way of gilgul shevuah (extending an oath): When he is imposing an oath on her in any case regarding her significant financial affairs, he may add a further oath that will include household matters as well - such as using household funds for other purposes - but only as an extension of the oath concerning her significant affairs.
In summary: In this mishnah we learned that a woman appointed to a financial role - as a storekeeper or as a guardian - may be required by her husband to swear at any time regarding her faithfulness with money. Rabbi Eliezer extends this even to a woman who was never appointed to any role, on the strength of the wool she spins and the dough she kneads; the Tanna Kamma, however, rejects an oath about household matters on their own, and permits it only by way of gilgul shevuah, as an extension of the oath concerning her significant financial responsibility.