Kesubos, Chapter 5, Mishnah 5. This mishnah lists all the tasks a wife is obligated to perform for her husband and for the household. The mishnah opens: "Eilu melachos she'ha'ishah osah le'ba'alah" - these are the tasks she is obligated to do for her husband. As we mentioned, the products of her labor belong to her husband, and therefore these are the things expected of her.
The tasks listed in the mishnah:
"Tochenes" - she grinds the wheat.
"Ofah" - she bakes the bread.
"Mechabeses" - she launders the clothing.
"Mevasheles" - she cooks the food.
"Menikah benah" - she nurses her child, and there is no need to hire a wet nurse.
"Matza'as lo hamitah" - she makes the beds.
"Osah batzemer" - she works with wool in order to prepare clothing.
If she brought maidservants with her - exemption from the tasks:
The more means the husband has to bring maidservants into the marriage who will work for them, the fewer the tasks that remain incumbent upon the wife:
One maidservant: "Einah tochenes, ve'einah ofah, ve'einah mechabeses" - these tasks are performed by the maidservant.
Two: "Einah mevasheles ve'einah menikah benah" - she need not even nurse the child, since a maidservant can be arranged to serve as a wet nurse.
Three: "Einah matza'as lo hamitah ve'einah osah batzemer".
Four: "Yosheves b'katedra" - she sits in a chair of honor and does nothing at all.
What is the difference between three and four?
The difference lies in the small tasks a woman does around the house. With three maidservants these tasks still fall upon her, whereas with four she is exempt even from those, and she may sit on her chair of honor and do nothing.
Nevertheless, the Gemara explains that there are certain things a wife does for her husband in any case, and these are acts of affection: pouring him a cup of wine and the like - acts that belong to the relationship between them, and are not considered work.
The mishnah continues: "Afilu hichnisah lo me'ah shefachos, kofeh la'asos batzemer" - even if she brought him a hundred maidservants, he may compel her to work with wool. The reason is so that she should not sit idle, for idleness leads to immorality: she is liable to stray and be drawn, Heaven forbid, after negative pursuits.
Similarly, one who makes a vow forbidding his wife to derive benefit from any work she does - he is compelled to divorce her and pay her kesubah, because he acted improperly. The reason: sitting idle and doing nothing leads to shi'amum, which means madness.
The Gemara discusses the difference between immorality and madness: if a woman occupies herself with games - such as playing chess and the like - this may still bring her to immorality, but not to madness, since at the very least she has something to occupy her mind.