Gemara

81b - Question: The Tana omitted other enactments of Yehoshua!

(Beraisa - R. Yishmael son of Rebbi Yochanan ben Berokah): Yehoshua made the inheritance of Eretz Yisrael conditional on these three enactments:

If Reuven's bees settled on a branch in Shimon's field, Reuven may cut off the branch to retrieve his bees and pay for the branch;

If Reuven's barrel of honey and it broke, and Shimon was carrying a barrel of wine (which is cheaper than honey), Shimon should spill out his wine to save the honey. Reuven pays to him the value of his wine.

If Reuven's donkey was carrying flax and died, and Shimon's donkey was carrying wood, Shimon should dump his wood and load the flax on his donkey. Reuven pays to him the value of his wood.

Answer: Our Tana lists only Tanayim that all agree about. Only one Tana holds that Yehoshua made these other enactments.

115a (Mishnah): If Reuven's jug of honey cracked, and Shimon spilled out his wine and saved the honey, he gets only his proper wage. If Shimon said 'I will save your honey and you will pay for my wine', Reuven must give him.

If a flooding river overcame the donkeys of Reuven and Levi, and Levi neglected his own donkey (worth 100) to save Reuven's (worth 200), he is paid only like a worker. If he said 'I will save yours and you will pay for mine', Reuven must pay.

115b - Question: Why does he get only like a worker? The honey was going to be lost, it is like Hefker!

Answer: The case is, there is a basket around the barrel (holding the shards in place. The honey would have dripped out slowly. It could have been saved.)

Question: Why can't Reuven say 'I was only joking!'?

(Beraisa): If Reuven was fleeing from jail, and he told the ferryman 'I will give you a Dinar to take me to the other side', he need pay only the standard fare.

This is because he can say 'I was only joking! We should say the same here!

Answer: Our case is like the Seifa;

(Seifa): If he said 'take a Dinar for your wages', he must pay the full wage.

(Rami bar Chama): The Seifa discusses a ferryman who was taking fish from the sea. In the time he crossed the river, he lost a Dinar's worth of fish.

Bava Metzia 30a (Rav Yehudah): If one's cessation from his work exceeds the value of the Aveidah, he is exempt from returning - "Lo Yihyeh Becha Evyon (do not bring yourself to poverty)" - (avoiding) your own loss takes precedence.

Bava Basra 8a: The Kaiser imposed a tax on the city of Tiverya in order to buy a crown. The ignoramuses threatened to leave if Chachamim will not share the cost. Rebbi refused, and half of them left. The Kaiser pardoned the city from half the original demand. The remaining ignoramuses made the same threat. Rebbi refused. They all left, except for one launderer. The kings' officers imposed the entire tax on him. He left, and the Kaiser totally pardoned the city.

Rebbi: This teaches that punishments only come due to ignoramuses.

Rishonim

Rif (41b): Some say that the Halachah follows the additional enactments that R. Yishmael taught. This is wrong. The Mishnah says that he gets only his proper wage. Also, the Gemara said that they are the opinion of an individual.

Rebuttal (Rosh 10:16): The Mishnah discusses one who voluntarily spilled his wine. R. Yishmael discusses when the owner of the honey tells him to spill his wine. The Tana did not list enactments of an individual, but the Halachah could follow them!

Rosh (7:18): When Reuven's barrel of honey broke, Shimon should spill out his wine to save the honey. Reuven to pays him the value of his wine. This is when there is a basket around the barrel. If not, the honey is Hefker.

Rambam (Hilchos Gezeilah 12:5): If Reuven's jug of honey cracked, and Shimon spilled out his wine and saved the honey, he gets only his proper wage. If Shimon said 'I will save your honey and you will pay for my wine', or he stipulated in front of Beis Din, Reuven must give him.

Rambam (6): If Reuven's jug of honey cracked, and Shimon had empty bottles and said 'I will saved the honey only of you will give to me half or a third', or such and such Dinarim, and Reuven agreed, he jested with him and gives only his proper wage, since Shimon did not lose anything.

Nimukei Yosef (Bava Basra Sof 5b): Rebbi told the ignoramuses to leave, for he knew that this would uproot the decree. If not, they may not leave. Once the king put the obligation on the city, there is a lien on all the residents and their property to pay. If water was coming to flood one's property, before it gets there he may divert it, i.e. seal his fence so the water will not enter. Once the water entered, he may not divert it (Yerushalmi Bava Kama 3:1). Once damage reached someone, he may not impose it on someone else.

Ra'avad (in Shitah Mekubetzes 117b DH uv'Emes): One may not save a large amount of his money with a small amount of Ploni's money in Ploni's absence. A Mishnah forbids cutting another's branch, with intent to pay, to save his own bees. If Ploni is here, he must consent to save another's money, since he will not lose. A Beraisa (Bava Metzia 30b) exempts from Hashavas Aveidah when he will not be compensated for his loss. This implies that when he will be compensated, he is obligated, e.g. to forfeit his wine or donkey to save another's honey or more valuable donkey. I lean to say that if Levi stipulates to compensate Ploni for his loss and he refuses, Levi may spill out Ploni's wine. Ploni is a Rasha for refusing, for he is obligated; Levi acts according to law. "Lo Yihyeh Becha Evyon" teaches that your Aveidah comes before others'. This refers to the Aveidah of one's Rebbi or father. There is no Isur to put one's own first. Perhaps even regarding others, one should not value his Sela more than 100 Sela'im of another. One should trust in Hash-m to repay him many times for the Mitzvah of Hashavas Aveidah.

Rashba (4:17): One who steals with intent to return in order to save his money is called a Rasha.

Mordechai (Bava Kama 193): If witnesses signed Sheker due to monetary Ones, they are Resha'im and Pasul for testimony, and must pay for the loss they caused.

Poskim

Shulchan Aruch (CM 264:5): If Reuven's jug of honey cracked, and Shimon spilled out his wine and saved the honey, he gets only his proper wage. If Shimon said 'I will save your honey and you will pay for my wine', or he stipulated in front of Beis Din, Reuven must give him.

Rema: Shimon is obligated to spill his wine, since Reuven offers to pay for it.

SMA (17): He must do Hashavas Aveidah because he has no loss from it.

Rema: Some disagree.

SMA (18): If a worker has an opportunity to do Hashavas Aveidah, and the owner of the Aveidah offers to pay what he will lose from his work, he is obligated. Here is different, for he can say that he prefers his wine (to another's wine that he will buy if he is compensated for the loss of his).

Shulchan Aruch (6): If Reuven's jug of honey and it cracked, and Shimon had empty bottles and said 'I will save the honey only if you will give to me half or a third', or such and such Dinarim, and Reuven agreed, he jested with him and gives only his proper wage, since Shimon did not lose anything.