Shevuos, chapter 6, mishnah 3. This mishnah focuses on an idea we have already discussed in an earlier mishnah: in the oath of one who admits to part of a claim, the admission must be of the same category as the claim - the same type of item that the claim was about. If the claim was about wheat, the admission must be about a certain quantity of wheat, and not about some other item. That is the subject of the mishnah before us.
The admission must be of the same category as the claim:
"Litra zahav yesh li beyadecha" - the claimant says that a certain measure of his gold is in his fellow's possession, and the fellow answers: "Ein lecha beyadi ela litra kesef" - meaning, that very same measure is in my possession, but of silver and not of gold. He is exempt from the oath of one who admits to part of a claim, because this is not of the same category as the claim: the claim was gold and the admission was silver.
"Dinar zahav yesh li beyadecha" - not a quantity of gold, but a gold coin, and the fellow answers: "Ein lecha beyadi ela dinar kesef ve'trisis ve'pundyon ve'perutah" - meaning, coins of lower value. Even though they are made of a different material - silver, and in the case of the perutah even copper - since we are dealing with coins and monetary values, it is all considered one category, and he is obligated in the oath of one who admits to part of a claim. In the words of the mishnah: "shehakol min matbea echad" - all forms of currency are considered one type, and a gold dinar is a large sum while a silver dinar, a trisis, a pundyon and a perutah are smaller sums than it.
"Kor tevuah yesh li beyadecha" - the claimant says that his fellow has in his possession a kor (thirty se'ah) of his grain, and the fellow answers: "Ein lecha beyadi ela letech kitnis" - meaning, half of that quantity (a letech is half a kor), but of legumes. He is exempt, since "tevuah" denotes one of the varieties of grain and not legumes.
"Kor peiros yesh li beyadecha" - here the claim is not specific to grain in particular, but to agricultural produce in general, and the fellow answers: "Ein lecha beyadi ela letech kitnis". He is obligated, "shehakitnis biklal peiros" - since the claim was not specific to grain, legumes are included in it.
A claim of wheat with an admission about barley - this is the classic case of an admission that is not about the same item, and therefore he is exempt.
The reason these cases are mentioned is the dissenting opinion: Rabban Gamliel disagrees with this very principle and holds that the admission need not be of the same category as the claim, and even though it is not the same category, he is obligated.
A claim of jugs of oil - the dispute between Admon and the Sages:
A person claims against his fellow that he has jugs of oil in his possession, and the fellow admits that the jugs are in his possession but denies the oil.
Admon: the claim was about the jugs and the oil together, and the fellow admits that the jugs are in his possession and denies only the oil. It turns out that he has admitted to part of the claim, and therefore he is obligated to swear.
The Sages: the admission about the jugs is not part of the claim and is not of the same category as the claim, since the claimant does not intend to claim the jugs themselves, but rather uses the expression "jugs of oil" the way people speak about oil - barrels full of oil. His real claim is the oil alone, and there is no admission to part of the claim here.
Rabban Gamliel: "Ro'eh ani es divrei Admon" - that is, his words are correct, and he is obligated to swear.
Oaths concerning land and the extension of an oath:
From here the mishnah moves to a different but related matter: one does not swear concerning land.
If one claimed against his fellow that he owes him vessels and land, and the fellow admitted the vessels and denied the land, or admitted the land and denied the vessels - he is exempt, because anything connected to land, whether in the claim or in the admission, is not subject to an oath.
If he admitted to part of the land - that is, the admission itself is within the land - he is exempt, because one is not made to swear concerning land.
If he admitted to part of the vessels and said: indeed I owe you some of the vessels you are claiming - he is obligated to swear. And not only that, but he swears about the land as well.
Even though one does not swear concerning land, there is a law known as the extension of an oath: once a person becomes obligated to swear about one thing, it is possible to include in his oath even matters about which he would not ordinarily have been obligated to swear.
And this is the conclusion of the mishnah: "shehanechasim she'ein lahem achrayus zokkin es hanechasim sheyesh lahem achrayus lishava aleihen" - property that has no security, meaning movable items that are not land, obligates an oath also concerning property that has security, which is land. They are bound up and extended together with the property about which he is obligated to swear, and even about the land, which ordinarily is not subject to an oath, he will swear.
In summary: In this Mishnah we learned that in the oath of one who admits to part of a claim, the admission must be of the same category as the claim, and we examined the cases that distinguish one category from another (gold and silver, coins, grain and legumes, produce and legumes, wheat and barley), as well as the view of Rabban Gamliel, who disagrees. We also examined the dispute between Admon and the Sages regarding a claim of jugs of oil, and the rule that oaths are not taken concerning land - and despite this, an admission to part of the vessels obligates an oath, which is then extended by rolling over to include the land as well.