Gemara

(Rava): All agree that a Milveh Al Peh (a loan without a document) cannot be collected from heirs!

22a (Rav Nachman): At first, I never collected from orphans' property;

After I heard Rav Huna cite Rav to say that orphans who consume others' (i.e. creditors') property should follow their father (i.e. die), I collect from their property.

Question: Initially, why didn't he collect?

Answer #1 (Rav Papa): Paying a creditor is a Mitzvah. Minors are exempt from Mitzvos.

Answer #2 (Rav Huna brei d'Rav Yehoshua): Perhaps the father gave Tzrari (a security) to his creditor.

These answers differ about one who admitted (just before he died) that he still owes, or he was excommunicated for not paying and died in Niduy. (Had he paid, he would have done so in Beis Din so they would end the Niduy.)

The Halachah follows Rav Huna brei d'Rav Yehoshua.

Bava Basra 5a (Reish Lakish): If Levi fixed a time to pay his debt to Yehudah, and claims that he paid within the time, he is not believed.

(Abaye and Rava): He is believed. Sometimes one gets the money and is eager to pay, lest he lose the opportunity!

5b: The Halachah follows Reish Lakish;

We apply the Chazakah even against orphans. Normally, one does not collect from orphans without swearing. If a man died before the time to pay his debt, the lender collects from the heirs without swearing, for there is a Chazakah that one does not pay before the time.

176a (Rav Papa): The Halachah is, a Milveh Al Peh is collected from heirs, due to Ne'ilas Delet (lest people be discouraged from lending).

Gitin 50a (Mishnah): When we collect land from orphans, we collect Ziburis (lowest quality land).

(Abaye Kashisha - Beraisa): Chachamim referred even to adult orphans, all the more so to minors.

The Halachah is, the enactments of swearing (in order to collect from orphans) and Ziburis apply to minor and adult orphans.

Kesuvos 93b (Mishnah): If a man married four women and he died, the first three must swear in order to receive their Kesuvos. The fourth receives her Kesuvah without swearing;

Ben Nanas says, also she must swear.

94a (Abaye): (The case is, adult orphans want the fourth woman to swear.) Ben Nanas holds like Abaye Kashisha, and the first Tana disagrees.

Rishonim

Rambam (Hilchos Malveh 11:6): A Milveh Al Peh is collected from orphans in only one of three ways. 1) Reuven (the borrower) admitted and commanded while sick that he still owes Ploni. 2) The loan was for a set time, and it did not arrive yet (when Reuven died), and there is a Chazakah that a man does not pay before the time. 3) Reuven was excommunicated until he will pay and he died in Niduy. In these three cases, we collect from orphans without a Shevu'ah. However, if witnesses testified that Reuven owed Ploni, he does not collect from the heirs at all, lest he paid. If one borrows in front of witnesses, he need not pay back in front of witnesses.

Rosh (Kesuvos 11:24): If the borrower died before the loan was due, there is a Chazakah that a man does not pay before the time, and the lender collects from the heirs.

Rosh (Bava Basra 1:9, citing R. Yonah): Even though we are not concerned for payment within the time, we are concerned for Tzrari even within the time. People are wont to deposit Tzrari within the time, and even at the time of the loan. This is why the Gemara explained that we do not collect from orphans due to Tzrari. It did not say that the concern is for payment, to teach that we are concerned even within the time.

Rebuttal (Rosh): It is not common to deposit Tzrari within the time. Even Abaye and Rava say only that perhaps he happened to get money and paid, lest he spend the money and will not have what to pay. Why should he deposit one of his articles within the time?! (Note - Rashi (22a DH Tzrari) says that Tzrari is coins, silver or gold.) If the lender will press him for payment when it is due, he can give an article then! Tzrari is common after the loan is due. The lender requests payment, and agrees to give more time if he gets a security, to be secure of getting his money. Therefore, one does not collect from orphans until they mature, lest they find witnesses that their father gave Tzrari. We do not mention payment, for concern for payment obligates only a Shevu'ah, but not to delay payment until they mature. Had he paid, he would taken back the document. We are not concerned lest there are witnesses that he paid and left the document with the lender, for this is not common. We are concerned for Tzrari within the time regarding a widow. There is different. Since it is a Tanai Beis Din (to pay the Kesuvah), there is concern for Tzrari even within the time. Kesuvos 102b says that there is more concern for Tzrari when there is a Tanai Beis Din. The Ritzva answered that also regarding a widow, the concern is lest he gave Tzrari when he was Shechiv Mera (dangerously sick), so she would not be disgraced in Beis Din.

Hagahos Ashri, citing Mahari'ach: If the father was alive, he would not be believed to say 'I paid'. Therefore, we do not claim this for the orphans. This is only from adult orphans. We do not collect from minor orphans. This is not only when we must accept witnesses, which cannot be done in front of minors (it is as if they are not here). Rather, even if witnesses testified in their father's lifetime, and Beis Din gave him time to pay and he died within the time, we do not collect from minors until they mature, unless there is Ribis (on a Nochri's loan) or to pay a Kesuvah and exempt the orphans from feeding her. Regarding minors, we are concerned for Tzrari even within the time.

Ran (Kesuvos 58b DH v'Hilchesa): Presumably, also when the borrower died before the loan was due, there is a Chazakah that a man does not pay before the time, and the lender collects from the heirs. In Bava Basra, we say that the Halachah follows Reish Lakish, even from orphans. One need not swear to orphans due to the Chazakah that people do not pay early.

Ran (ibid.): Some disagree, and say that there we collect only from adult orphans without a Shevu'ah. Regarding minor orphans since we are concerned for Tzrari, we are concerned even within the time. We would have been concerned regarding a widow, if not for Chen (to encourage marriage) or (exempting the orphans from paying for her) food, even though it is within the time; a (widow's) Kesuvah cannot be collected in his lifetime. If it were true (that we collect from orphans if he died before it was due), the Gemara should have taught this among the cases in which we collect from orphans. This would have been a bigger Chidush (even though normally we do not collect, within the time we collect).

Rebuttal (Ran, ibid.): We collect without a Shevu'ah even from minor orphans. Within the time there is no concern for Tzrari. If there were concern, why do we collect from adults without a Shevu'ah? We should impose an oath due to concern for Tzrari! A Kesuvah is different, for it was normal to leave the Kesuvah on the table. It was needed to enact not to do so (it is better that there be a lien on his property to pay the Kesuvah, to discourage divorce - Kesuvos 80b)! In Bava Basra the Gemara did not teach (that the Chazakah permits collecting from minor orphans), for one might have thought that a Shevu'ah is required. Therefore, it taught that no Shevu'ah is needed, for adults or minors. Also R. Yehudah Albartzeloni and the Rambam say so.

Poskim

Shulchan Aruch (CM 108:1): A Milveh Al Peh is collected from orphans in only one of three ways.

SMA (1): It is not collected even from adult orphans. Since Reuven would have been believed to swear Heses that he paid, we claim for orphans whatever their father could have claimed. They need not swear that they do not know that their father owed. We say so only regarding severe oaths, e.g. when orphans come to collect with a document and the borrower says that he paid.

Gra (1): Even though Rav Papa exempts only minor orphans, Rav Huna exempts even adults, since we claim for them. The Gemara did not say that Rav Papa and Rav Huna argue about adults, because Ben Nanas and Chachamim argue about this, but we hold like Abaye Kashisha (that one must swear in order to collect even from adult orphans).

Shulchan Aruch (ibid.): 1) Reuven (the borrower) admitted and commanded while sick that he owes Ploni.

SMA (2): If he commanded when he was sick, we do not say that it was so people will not think that his heirs are rich.

Shach (1): Even if he admitted when he was sick, he can say that it was lest people think that his heirs are rich (CM 81:14)! Rather, we discuss a case in which he cannot say so (e.g. he admitted to a claim against him).

Shulchan Aruch (ibid.): 2) The loan was for a set time, and it did not arrive yet (when Reuven died).

Beis Yosef (DH v'Hu): The Tur equates a loan that is not yet due to the other cases (in which one must pay orphans), for there is no concern for Tzrari. There is a Chazakah that a person does not pay within the time. The Rambam says that there is no concern for Tzrari. One collects even from minor orphans. The Magid Mishneh (12:1) explains the Rambam like this, and says that the Ramban and Rashba agree. The Ran brought an opposing opinion, and rejected it. Also Sefer ha'Terumah brought an opposing opinion. He rejected it; the Gemara mentioned one (or two) way(s) of collecting, and there are also others.

Gra (2): The Gemara did not say that Rav Papa and Rav Huna argue about when he died within the time, for they argue with Reish Lakish there.

Shulchan Aruch (ibid.): 3) Reuven was excommunicated until he will pay, and he died in Niduy. In these three cases, we collect from orphans without a Shevu'ah. However, if witnesses testified that Reuven owed Ploni, he does not collect from the heirs at all, lest he paid.

Rema: However, if the heirs claimed that their father never borrowed, it is as if they said that the debt was not paid

SMA (5): This is if the orphans claimed that Vadai he never borrowed. A Vadai claim of an heir is as if his father claimed. If they are not Vadai, orphans and overseers can claim like they want and retract and make new claims.

Shulchan Aruch (ibid.): Similarly, if Ploni showed a document written in Kesav Yado, he does not collect with it at all, lest he paid it.