Gemara

(Mishnah): If Levi was Makdish his property, or was Ma'arich himself, the Gizbar has no rights to take (for Hekdesh or collateral) the clothing of Levi's wife and children, nor clothes dyed for them or shoes bought for them.

Bava Kama 102b (Beraisa): If Reuven gave money to a Shali'ach (Shimon) to buy wheat, and he bought barley with it, if it went down in value, Shimon suffers the loss. If it went up in value, they share the gain.

(R. Yochanan): This is like R. Yehudah, who holds that one does not acquire through Shinuy (change).

Rebuttal (people of Eretz Yisrael): According to R. Yehudah, how does Reuven acquire half the grain (to share the profit)? The seller did not know (that Shimon deviated) to intend that Reuven acquire!

Question (R. Shmuel bar Sasarti): If so, even when he bought like Reuven requested, how does Reuven acquire?

Answer (R. Avahu): When Shimon acts like a Shali'ach of Reuven, it is as if Reuven bought it.

Question (Mishnah): If Levi was Makdish... the Gizbar has no rights to clothes dyed for Levi's wife and children, or shoes bought for them.

We should say that the seller or dyer) did not know to intend that the wife (or children) should acquire!

Answer #1: Rather, Levi acts like a Shali'ach of his wife and children. It is as if they bought them.

Rejection #1 (and Answer #2 - R. Aba): We need not say that Levi was their Shali'ach. Rather, one who makes Hekdesh does not intend for the clothing of his wife and children.

Question (R. Oshiya - Mishnah): If one is obligated to pay Erchin, we take securities from him (against his will).

Does one intend that we take securities from him against his will?!

Rejection #2 (and Answer #3 - R. Aba): When one makes his property Hekdesh, it is as if he gave his wife and children ownership of their clothing beforehand.

Kesuvos 54a (Rav): We evaluate the clothing that a widow is wearing (towards payment of her Kesuvah).

(Shmuel): It is not deducted from her Kesuvah.

(Rav Nachman): Even though a Mishnah supports Shmuel, the Halachah follows Rav.

. i. (Mishnah): If one made his property Hekdesh, the Gizbar does not collect from his wife's clothing...

(Rav Nachman): Really, the Mishnah does not support Shmuel. The Gizbar does not collect from her clothing, because the husband gave it to her to wear in front of him (i.e. during the marriage). He did not give it to her to leave with it.

Rishonim

Rambam (Hilchos Malveh 1:5): A creditor does not collect from the clothing of the borrower's wife and children, not from colored clothing that was dyed for them, even if they did not wear it yet, nor from new shoes that he bought for them. They belong to them (his family). This refers to weekday clothes. A creditor collects from Shabbos and Yom Tov clothing, and all the more so rings and gold or silver Kelim.

Hagahos Ashri (Bava Kama 9:18 DH uched'Masik): We conclude that it is as if he gave his wife and children ownership of their clothing. The Ri derives from here that one cannot sell clothing that he bought for his wife, even if she did not get it yet. We learn from a Kal va'Chomer from Hekdesh. Even if he has no way to support himself, he cannot sell it. Mahari'ach says that the conclusion is only regarding Makdish or Ma'arich. We do not say so for a creditor. It seems that this is a mere Dichuy (a flimsy rejection). Really, a creditor has the same law. He does not collect from the things that the Mishnah mentions. When he bought it for them, they acquired. He was a Shali'ach for them, like the Gemara said initially. If he sold their clothing, it is void.

Rashba (102b DH Ha): R. Aba answered that it is as if he gave his wife and children ownership of their clothing beforehand. He did not say 'whoever is Makdish (intends...)' This suggests that Lev Beis Din Masneh (Chachamim stipulated about this). This is wrong. If so, it would apply only to Hekdesh. In Kesuvos, the Gemara wanted to learn from here to a Kesuvah! This shows that this is letter of the law. We can testify that a man intends that they acquire Kelim that he buys for them, even if he did not explicitly say so. We estimated his intent. We say similarly in Bava Metzia (34a, that if a deposit was stolen and the Shomer decides to pay and not swear), that the owner was Makneh (transferred ownership of) it to him before the theft, in order that the Shomer will receive Kefel (double payment) if the thief is caught). However, according to R. Aba, he was not a Shali'ach to acquire for them when he bought it. Rather, afterwards he was Makneh to them, like we say that 'whoever is Makdish... (does not intend for their clothing. This shows that he owns it!) Also, R. Aba disagrees with R. Avahu and says that in the Mishnah, he was a Shali'ach for them. Who acquires for them (according to R. Aba)? We can say that whenever one feels great closeness, he resolves to acquire for them, and this helps even to uproot from Hekdesh mid'Oraisa. We find like this in Avodah Zarah (63b) regarding a grocer who normally sells on credit. It is as if the grocer receives the money right away. Alternatively, here it is not due to acquisition. Rather, one does not intend for what he bought for his wife and children, like we say in Nedarim (46b; see Rashba there, DH v'Ika) about a bathhouse or olive press rented out to others. This is primary.

Poskim

Shulchan Aruch (CM 97:25): A creditor does not collect from the clothing of the borrower's wife and children...

Beis Yosef (DH ba'Meh): The law of Sidur (leaving a debtor with his needs) for a creditor is like for Erchin, for we learn it from Erchin.

SMA (59): A creditor does not collect from what he dyed or bought for them, for what he acquired to them is as if he sold to others. A creditor does not collect from sold Metaltelim. Even if the Metaltelim were acquired Agav (along with) land after the loan, the creditor does not collect from them, just like he does not collect from property that the borrower bought and sold after he borrowed. The Tur brought in the name of the Ramban that if the borrower gave a lien to the lender on Metaltelim Agav land, and wrote d'Akni (what I will acquire), he collects from the borrower's wife and children. The Mechaber omitted this. I say that that this is because the Acharonim enacted that even if one writes d'Akni, he does not collect from sold Metaltelim. This is for the sake of business (lest people be afraid to buy). Even though there was no such enactment for business regarding one who borrowed twice, and even if the latter lender collected first, even Metaltelim, the first lender collects from him if he wrote d'Akni, a wife is considered a buyer. There is no distinction regarding buyers. The enactment for business applies to all of them. Only nowadays they enacted to collect from this (when he wrote d'Akni), due to swindlers.

Gra (85): In Bava Kama, we say 'when one makes his property Hekdesh, it is as if he gave his wife and children ownership of their clothing beforehand.' This is a mere Dichuy, according to people of Eretz Yisrael. We do not hold like them, like Hagahos Ashri says. The Rashba says that even people of Eretz Yisrael hold that it is not only for Hekdesh. The same applies to everything. The reason is like it says in Kesuvos (which learned from Hekdesh to collection of debts).

Pischei Teshuvah (12): Sha'ar Mishpat (6) says that a creditor does not collect from the wife's clothes in her husband's lifetime, but if he died, he collects from her clothing. Even though she is entitled to collect her Kesuvah, the creditor has precedence.

Shulchan Aruch (ibid.): He does not collect from colored clothing that was dyed for them, even if they did not wear it yet, nor from new shoes that he bought for them.

SMA (60): Even if he did not buy for them, rather, he wove or bought them for himself, and later decided to designate them for his wife (or children) and dyed them for them, they acquire through the Shinuy, and the creditor does not collect from them. This is unlike Seforim which are in his hand. They are like his property; the creditor collects from them.

Shulchan Aruch (ibid.): Also, he does not collect from Seforim that he bought for his children to learn from. They belong to them (his family).

Beis Yosef (DH v'Chasav): R. Yehudah Albartzeloni says that the same applies to Seforim that he bought for his children to learn from. I agree, for his children already acquired them, so a creditor does not collect from them. We do not leave a borrower with more than 12 months (of clothes), but we leave for his wife and children even more than 12 months for this reason. Sefer ha'Terumah disagreed, for the Mishnah taught clothing, and not Seforim. This is not a proof. The Tana is not a peddler! He taught clothing, and the same applies to Seforim!

Prishah (45 DH v'Lo): The Tur says that a creditor collects from the borrower's Seforim, and all the more so from those he bought for his children. They are not needed as much as food or clothing. One can learn from others' Seforim!

Gra (86): He cannot collect from his wife and children's clothing. The same reason applies to Seforim, like it says in Bava Kama (it is as if he acquired to them).