Bava Metzia

A certain heathen gave a house in pledge  to R. Mari b. Rachel,  and then sold it to Raba. Thereupon he [R. Mari] waited a full year, took the rent, and offered it to Raba.  Said he to him: 'The reason that I have not offered you rent before this is that an unspecified pledge is a year. Had the heathen wished to make me quit [within the year], he would have been unable;  but now you must take rent for the house'. He replied: 'Had I known that it was pledged to you, I should not have bought it. Now I will treat you according to their laws; for until they redeem the pledge  they receive no rent; so I will take no rent from you until you are paid out'. Raba of Barnesh  said to R. Ashi: See, Sir, the Rabbis enjoy  usury. For they advance money for wine in Tishri, and receive choice quality in Tebeth!  He replied: They too pay their money for wine, not vinegar, and from the very beginning, wine is wine, and vinegar, vinegar;  it is then [when they pay] that they select choice wine. Rabina gave money [for wine] to the residents of Akra dishanwatha,  and they supplied  a liberal addition.  So he went to R. Ashi and asked him: Is it permitted?  Yes, he replied; they but forego [their rights] in your favour.  But, said he, the land is not theirs!  — The land is pledged for the land tax, he replied, and the king has decreed: He who pays the land tax is entitled to the usufruct. R. Papa said to Raba: See, there are some scholars who advance money for people's poll tax and then put them to much service! — He replied: I might have died, without telling you this thing. Thus said R. Shesheth: The surety  of these people lies in the king's archives, and the king has decreed that he who does not pay his poll tax is made the servant of him who pays it [on his behalf]. R. Se'oram, Raba's brother, used to seize people of disrepute and make them draw Raba's litter. Said Raba 'to him: You have done well. For it has been taught:  If you see a man who does not behave in a seemly fashion, whence do we know that you may make him your servant? From the verse, They [sc. Canaanite slaves] shall be your bondmen for ever and your brethren the children of Israel [likewise].  I might think that this is so even of one who behaves in a seemly fashion; therefore it is taught, but over your brethren, the children of Israel, ye shall not rule one over another with rigour. R. Hama said: If a man gives his neighbour money to buy wine for him, and he negligently fails to do so, he must compensate him as it is sold in the market of Belshafat.  Amemar said: I repeated this ruling before R. Zebid of Nehardea, whereupon he observed: R. Hama's dictum applies only to unspecified wine, but not to a particular wine, [for] who knows that he could have obtained it for him?  R. Ashi said: Even for unspecified wine it is also not [correct]. Why? Because it is an asmakta, and an asmakta establishes no legal claim.  But in R. Ashi's view, how does this differ from what we learnt: [If the tenant-farmer declares], 'If I let it lie waste without cultivating it, I will pay with the best [of produce,'  he is bound to do so]? — There it is in his power [to cultivate it];