Arachin, Chapter 7, Mishnah 1. With this perek the masechet enters its final three chapters, which take up an entirely fresh topic: a person who dedicates ground in Eretz Yisrael to the Beit Hamikdash. Our perek opens with three mishnayot about a man who sanctified the field he inherited from his forefathers and now wants it back in his own hands by paying Hekdesh for it. Before the mishnah can be followed, a short background on how fields are held in the Land is needed.
Land in Eretz Yisrael and the Yovel
The Torah rules that ground sold in the Land does not stay sold. In the fiftieth year, the Yovel, the field returns to the family that received it as its portion when Yehoshua bin Nun and the nation conquered and divided the country, and which has passed it from father to son ever since. Trace any field back far enough and you arrive at that first ancestor; a field with such a lineage is termed sdeh achuzah, a field of inheritance. Because it inevitably comes home to that family in the Yovel year, buying real estate in Eretz Yisrael is never a permanent acquisition. What looks like a sale functions more like a long term rental.
The Torah gives a parallel set of laws for a field that is consecrated to Hekdesh and later redeemed from the temple treasury. If the owner redeems his ancestral field before the Yovel arrives, the field is his once again. But if the Yovel arrives and he has not redeemed it, or if somebody else redeemed it or purchased it from the treasury first, the field is lost to him permanently. In that case the Yovel offers him no help at all.
Redemption from the Beit Hamikdash is not transacted at market value. The Torah fixes the sum according to how many years are left until the next Yovel. Someone who sanctifies a field and redeems it right at the start of a new cycle pays fifty shekalim for a plot of beit kor, an expanse of thirty beit se'ah. Redeem further along, and the years already spent are subtracted, so that the charge covers only what still lies ahead. Because a cycle runs forty nine years, a single year comes to a shekel and a fraction: fifty shekalim spread across forty nine years.
Practical advice: stay away from the final two years
The mishnah begins with guidance for a man weighing whether to sanctify his inherited field when the Yovel is almost upon him. "Ein makdishin lifnei haYovel", one does not dedicate a field ahead of the Yovel, "pachot mishtei shanim", when fewer than two years are left.
No prohibition is being stated here; the mishnah is guarding the man's wallet. A gezerat hakatuv, a ruling learned from the verses, establishes that once the remaining time has dropped under two years, one who buys his inherited field back from the treasury is charged the entire fifty shekalim rather than the modest figure matching the year or two still on the clock. Compare him to a man redeeming two years into the cycle, who subtracts what has already gone by and lays out something in the neighborhood of forty seven shekalim. At the tail end of the cycle the numbers invert: almost nothing remains, and the Torah nevertheless demands all fifty. Buying back so brief a stretch of time is ruinously expensive.
And realistically he will want the field back, since a field not redeemed by the time the Yovel comes leaves the family for good. So the mishnah's counsel is financial: keep away from dedicating your inherited land during the closing two years of the cycle. Nothing stops him if he insists, but he has made an expensive mistake.
Redemption is reckoned in whole years
"Velo go'alin le'achar haYovel", and one does not redeem after the Yovel, "pachot mishanah", for a span shorter than one whole year. A man who arrives to redeem partway through a year cannot pay a fraction of it; that year is billed to him in its entirety.
Take someone redeeming six months after the Yovel. He would like to argue that only half a year has gone by, so forty eight and a half years of value remain and that is what he should pay. The mishnah teaches otherwise: the partial year counts as a whole year, and he pays for forty nine. The same rule holds at every point in the cycle. Whenever a person stands in the middle of a year, that year is reckoned in full, and the portion of it that has already passed cannot be shaved off the total. The redemption price is always calculated in complete years, and this too is derived from the pasuk.
Two rules that seem to pull in opposite directions
At first glance the two rulings collide. With five and a half years left, the owner is billed for six, so the leftover half is rounded up into a complete year. Why should the same logic not apply when a year and a half remains? If half a year can register as a year, then a year plus a day ought to register as two, placing the owner outside the restricted window and entitling him to the annual rate rather than the flat fifty shekalim. One halachah swells a fragment into a whole; the other refuses to. What decides which direction the fragment moves?
The mishnah's answer: "Ein mechashevin chodashim lahekdesh", months are not calculated to the benefit of the one paying, "aval hahekdesh mechashev chodashim", but Hekdesh itself does calculate months when it stands to gain. A man settling with the treasury may not slice the year into halves and quarters; the full year is charged. Forty seven and a half years remaining means paying for forty eight. Every rounding runs to Hekdesh's advantage. Hekdesh, for its part, will gladly count months whenever counting them serves it. Hence, with a year and a half still on the clock, that half year is not inflated into a second complete year. It is called what it is, under a year, which places the man inside the final two year stretch, and the whole fifty shekalim come due.
Calculating the price of the sdeh achuzah
Now the mishnah lays out the actual numbers. "Hamakdish et sadehu bish'at haYovel": a man who sanctifies his inherited field during a period in which the Yovel is functioning. Yovel applies only while most of Israel dwells in the Land with every shevet settled on its own portion. Where Yovel is not observed, redemption follows fair market value rather than the Torah's fixed scale. The figures that follow belong to an era of active Yovel, and the case described is a man redeeming during the year that follows the last Yovel.
"Noten bezera chomer se'orim", he pays for ground that absorbs a chomer of barley seed, "chamishim shekel kasef", fifty shekalim of silver. That measure of ground is the beit kor described above.
"Hayu sham neka'im", if the plot contained crevices, "amukim asarah tefachim", ten tefachim deep and filled with water, "o sla'im gevohim", or boulders rising, "asarah tefachim", ten tefachim high, then "ein nimdadim imah", they do not enter the measurement. The space they occupy is left out of the acreage priced at fifty shekalim, because that rate was legislated for arable soil, not for water logged gullies or protruding rock where nothing grows.
"Pachot mikan, nimdadin imah". Crevices shallower than ten tefachim and rocks lower than ten tefachim are included in the measurement. Halachically they are batel, negligible against the field as a whole, so those patches are counted in when the beit kor is measured out, and they are redeemed at the fifty shekel rate along with everything else.
Redeeming later in the cycle
Everything until now assumed redemption during the opening year of the cycle. What about a man who comes later? "Hikdisha shtayim o shalosh", if he sanctified it two or three "shanim lifnei haYovel", years prior to the Yovel, then "noten sela upundeyon leshanah": the charge is one sela plus one pundeyon, a tiny coin, for every year still remaining. Two full years left, meaning genuinely more than two and therefore clear of the restricted window, comes to two sela'im together with two pundeyonot. The peculiar figure comes from the division seen earlier: fifty shekalim cover forty nine years, so one year works out to a shekel plus a small remainder. Fifty is the price of the entire forty nine year span, and a single year's share is that average, a shekel and change.
No paying in installments
May the money be spread out across the years? "Im amar harenei noten", if the one redeeming proposes, I will pay "devar shanah beshanah", the amount due for each year as that year arrives, instead of producing the total up front, the mishnah responds "ein shom'in lo", his proposal is turned down, "ela noten et kulo", he hands over the entire sum, "ke'echad", in one payment. Wanting the field back means paying in full on the spot. The pesukim teach this as well: Hekdesh does not do payment plans.