Terumos Chapter 1, Mishnah 5. This mishnah teaches one fundamental principle: when a person separates Terumah from one batch of produce on behalf of another batch, both must be on the same level in terms of their Terumah obligations, and only then does the separation take effect.
Let us illustrate. We have two buckets before us, bucket A and bucket B, each containing fifty cups of grain - one hundred cups in all. The measure of Terumah Gedolah is one fiftieth, so a person may take one cup from bucket A and one cup from bucket B, or he may take two cups from bucket B alone and say: "These two cups are Terumah for all one hundred cups in both buckets together." In this way both vessels, A and B, are properly set right.
However, this separation works only on condition that both vessels are equally obligated in Terumah. If their status is not equal, for whatever reason, the separation does not take effect. That is the point of the mishnah: it lists a series of possibilities for what might be found in vessel B, and in each of them, if vessel A contains ordinary produce that is obligated in Terumah while vessel B contains one of the listed categories, it no longer works to separate from vessel B on behalf of vessel A.
"Ein torlmin min haleket umin hashichechah umin hapeah":
A person may not separate Terumah from bucket B for both buckets together when bucket B contains leket, shichechah or peah. What are these three, which were already taught in Maseches Peah?
Leket - one or two stalks that fall while the grain is being harvested in the field, which must be left for the poor to gather.
Shichechah - one or two sheaves that were forgotten in the field when the sheaves were brought to the threshing floor for processing. The owner may not go back and take them; he must leave them for the poor.
Peah - the obligation to leave a portion of the field unharvested, as standing grain, for the poor to come and collect.
All three are gifts to the poor, and all of them are exempt from the obligations of tithes. A poor man who goes and gathers his leket, shichechah or peah need not tithe them and does not separate Terumah from them. And since what is in vessel B is exempt from the obligations of tithes while vessel A is obligated in Terumah, taking the Terumah from vessel B on behalf of vessel A does not work.
"Umin hahefker":
Hefker means produce that has no owner, and it is exempt from the obligations of tithes. There are two types of hefker before us:
Produce that grew on its own - this is the main category the mishnah is dealing with: grain that grew wild in the field, and is therefore ownerless and exempt from the obligations of tithes. Even if a person comes and gathers this wild grain from the fields, it is exempt from Terumah obligations, and one does not take Terumah from it on behalf of vessel A.
One who declares his produce ownerless - a person who had produce in hand and said: "I have more than I need; I am placing it on the porch in front of my house, and whoever wants may come and take. It is hefker." This too is hefker, but it exempts only in limited circumstances: only if the declaration renouncing ownership was made before that produce became obligated in the separation of tithes.
The moment at which the obligation of tithes takes effect is called 'gemar melachah', that is, the completion of the processing of that food:
For grain - miruach hakri, the smoothing over of the pile of grain at the end of the process.
For oil - the completion of pressing the oil and storing it in jugs, since with oil there is no pile.
For wine - the completion of pressing the grapes and collecting the wine into jugs or into storage.
Accordingly, if a person said after the fact, "I have more wine than I need," and set aside a few bottles for whoever wants to take them, and that wine had already reached the stage at which its processing is complete and no tithes had been separated from it - the wine is obligated in separation even though it was declared ownerless, and if vessel B were full of such wine, one could indeed separate from it for vessel A. It emerges that the ownerless produce in our Mishnah is one of two things: produce that grew wild and never belonged to anyone and never became obligated in tithes, or produce that did belong to a person and he relinquished his ownership before the tithing obligations took effect.
And why is ownerless produce exempt from tithing obligations? The verse gives a reason for the obligation of tithing in the first place: the tribe of Levi, including the kohanim who receive Terumah, received no portion or inheritance in the Land of Israel, and therefore it depends on the rest of the population, who own land, to supply it with produce. And this is the language of the verse: "Uva haLevi ki ein lo chelek venachalah imach" - the Levi comes and takes a gift, because he has no portion or inheritance in the land along with you. But with ownerless produce, the Levi's share and your share are equal, and the Sages expounded: "Yado veyadcha shavin" - your hand and his hand have equal access to that produce, and therefore there is no obligation to give tithes from it to the Levi.
"Velo mimaaser rishon shenitlah terumaso":
Maaser rishon is the gift given to the Levi, normally after Terumah Gedolah has been separated from the produce. Obviously, if we are dealing with ordinary food whose Terumah was separated and which was then given as maaser, there is no further obligation to tithe it and it is exempt produce, and one does not take from it in vessel B for what is in vessel A, which is still obligated in Terumah. So that is not our case.
Our case is a Levi who took his portion early. The normal order of operations is that first Terumah Gedolah is separated for the kohen, and from what remains ten percent is given to the Levi as maaser rishon. But here the Levi came before the processing of the grain was completed, while it was still in the stalks, and said, "Do me a favor and give me my portion now." Since he took the produce before it reached the stage that would obligate it in Terumah Gedolah, that portion will never become obligated in Terumah Gedolah, and consequently the Levi's share is slightly larger, since he gives none of it to the kohen.
Even so, one obligation remains on this maaser rishon: the separation of terumas maaser. Just as the Yisrael gives a portion of his grain to the kohen as Terumah Gedolah, so the Levi gives a portion of what he received as maaser rishon, and his portion is called terumas maaser. Once terumas maaser has been separated and given to the kohen, if the Levi has two vessels, and in vessel B is that maaser rishon whose Terumah has already been taken, he cannot separate from it to exempt what is in vessel A from the obligation of Terumah Gedolah.
From here an important inference emerges, based on a verse and its exposition: if terumas maaser has not yet been separated from that maaser rishon, it is still obligated, and one may separate from what is in vessel B as Terumah Gedolah for what is in vessel A. You learn from this that Terumah Gedolah and terumas maaser are equal in status, and are essentially one and the same thing; it is only that Terumah Gedolah comes from the Yisrael who owns the land, while terumas maaser comes from the Levi's portion.
"Velo mimaaser sheni vehekdesh shenifdu":
Two separate matters are before us: maaser sheni, and hekdesh - property consecrated to the Beis HaMikdash. Even if they were redeemed, meaning that their sanctity was removed from them and transferred to coins, they are exempt from the separation of Terumah, and consequently if they are in vessel B, it does not serve as a source for separating Terumah for what is in vessel A.
Maaser sheni: after Terumah Gedolah and maaser rishon have been given, in years one, two, four and five of the seven year cycle one separates an additional tenth from what remains, in order to bring it up to Jerusalem and eat it there. The Tanna of our Mishnah holds that this maaser sheni does not belong to its owner at all; rather it is 'mamon gavo'ah' - property belonging to Above, the food of the Holy One, blessed is He. And when a person goes up to Jerusalem and eats it there, it is as though the Holy One, blessed is He, invites him to sit with Him at His table and share in His meal. And since it is not the property of a private individual, it does not become obligated in Terumah and tithes at all.
But our Mishnah teaches something beyond this: even after it has been redeemed. How so? One who separated that tenth may choose not to bring the food up to Jerusalem, but rather to transfer the sanctity contained in it to silver coins, and to go up to Jerusalem with the money and buy food with it, and the sanctity passes back from the money to the food, which is eaten there as maaser sheni. This redemption converts the status of the food from the sanctity of maaser sheni into ordinary, unconsecrated food. Even so, and even though Terumah was never separated from it, it is exempt from separation, and it is not a legitimate source from which to separate in vessel B for what is in vessel A.
Hekdesh that was redeemed: a person may give one of his assets to the Beis HaMikdash, and by giving it he causes the sanctity of hekdesh to rest upon it. There are two categories here:
Something fit for the Altar - for example, one who dedicates his cow. An inner, absorbed sanctity takes hold of it, one that never departs from it.
Something that has no place on the Altar - such as a pen or apples. Their sanctity is the sanctity of bedek habayis, property held for the upkeep of the Beis HaMikdash. The Temple will eventually sell them at public auction, and the moment the buyer hands over his money the sanctity leaves the object and passes to the money now in the Temple's possession, while the object becomes completely unconsecrated.
Here is our case: a person dedicated his wheat field to the Beis HaMikdash. As long as the field is in the hands of hekdesh it is exempt from tithes, since the Beis HaMikdash is not a private individual, and the verses that obligate Terumah and tithes do not apply to it. Once the Temple put the field up for sale and a member of the public redeemed it, the question arises whether the grain in the field is obligated in tithes, and the answer depends on the timing:
Redeemed after the work was completed - once the grain has been harvested, threshed, winnowed and piled up, the point at which the obligation of Terumah should have taken effect has already passed, and it did not take effect because the grain was Temple property. Now it is too late, and it will never become obligated in tithes.
Redeemed before the work was completed - the buyer is the one who will finish processing the grain under his own responsibility, and since he is a private individual the obligation of tithes falls upon him. It makes no difference that the grain once belonged to the Temple.
Our Mishnah, then, is dealing with hekdesh that was redeemed after the work was completed, which is permanently exempt from tithes. And if that is the wheat in vessel B, he cannot separate from it for what is in vessel A.
The Mishnah continues - pairs from which one may not separate for the other:
"V'lo min hachiyuv al hapatur, v'lo min hapatur al hachiyuv" - if what is in vessel B is obligated in tithes while what is in vessel A is exempt from them for some reason, such as that it did not grow to full size before it was harvested, and likewise in the reverse case. Since their status is not equal, one does not take from vessel B on behalf of vessel A.
"V'lo min hatalush al hamechubar, v'lo min hamechubar al hatalush" - talush means produce that has been detached from the ground, and mechubar means produce still attached to the ground. A person does not tithe his grain while it is still attached to the ground, and therefore he cannot designate Terumah from the detached for the attached, nor from the attached for the detached.
"V'lo min hechadash al hayashan, v'lo min hayashan al hechadash" - the reference here is not to the chadash of the Omer offering, but to this year's crop as opposed to last year's crop.
For grain, the tax year changes at Rosh Hashanah, on the first of Tishrei, and therefore grain that grew before Rosh Hashanah is considered old, while grain that grew after it is considered new. The reason one may not tithe from one for the other is a separate verse requiring that each year be tithed on its own: "Aser te'aser es kol tevuas zar'echa hayotzei hasadeh shanah shanah" - "You shall surely tithe all the produce of your seed that the field brings forth, year by year" - "shanah shanah", teaching that each year requires its own tithing. (For fruit of the tree the tax year is different, as you will recall, and their Rosh Hashanah is on the fifteenth of Shevat.)
"V'lo mipeiros ha'aretz al peiros chutz la'aretz, v'lo mipeiros chutz la'aretz al peiros ha'aretz":
Produce that grew in Eretz Yisrael is obligated in tithes, while produce of outside the Land is exempt, and since their status is not equal one does not separate from one for the other in either direction. And here lies the novel point: there are several lands adjacent to Eretz Yisrael which, although exempt from tithes by Torah law, the Sages obligated in tithes:
Bavel - present-day Iraq.
Egypt - to the south.
Ammon and Moav - present-day Jordan.
Surya - present-day Syria.
All of these regions are obligated in tithes by rabbinic law. Therefore, if vessel A contains food from Eretz Yisrael and vessel B contains food from Surya, even though both require tithing, one does not take from vessel B to exempt vessel A, nor the reverse, since the obligation of Surya's produce is only rabbinic while the obligation of Eretz Yisrael's produce is from the Torah, and their status is not equal.
The Mishnah concludes: "Im tarmu ein terumasan terumah" - if he nevertheless separated from vessel B for vessel A in any of these cases, what he separated is not Terumah at all, and the separation is null and entirely without force.
In summary: Our Mishnah established a single principle: Terumah may not be separated from one batch of produce on behalf of another unless both are equal in status and in their obligation. On this basis the Mishnah listed those items that are invalid for separation: leket, shich'chah and pe'ah, which are gifts to the poor; ownerless produce, which never became obligated in tithes; first tithe, from which its Terumah has already been taken; second tithe and consecrated produce that have been redeemed; produce that is obligated as against produce that is exempt; detached produce as against produce still attached to the ground; new crop as against old crop; and produce of the Land of Israel as against produce grown outside the Land. In all of these cases, if one did separate Terumah, the separation is not valid.