Arachin, Chapter 2, Mishnah 1. The first chapter established who is fit to make an erech vow and whose erech can be pledged. This chapter opens with a series of rules built on a single style of phrasing: in this area of halacha there is never less than a certain amount and never more than a certain amount. The mishnah applies that formula first to arachin, and then, because the phrasing invites it, to two other subjects entirely.
What an erech vow is
Someone who declares his own erech, or the erech of another person, becomes liable for a fixed sum that goes to the funds of the Beit Hamikdash. No appraisal of the individual takes place. Scripture itself assigns the figures by age and by gender, and each bracket carries its own precise number. The ceiling is fifty sela'im, owed for a male from the age of twenty until sixty. The floor is three sela'im, owed for a female from one month old until the age of five.
The Torah also makes room for a pledger whose means fall short of what he undertook. He presents himself to the kohen, the kohen evaluates his situation and what he can actually afford, and a smaller figure is fixed in place of the original one. Our mishnah opens by teaching that even this leniency stops somewhere: however poor the pledger may be, there is a sum beneath which he cannot go.
The floor and the ceiling
"Ein ba'arachim pachot misela."
Nobody discharges an erech vow with less than a single sela, and at the other end nothing exceeds "chamishim sela", fifty sela'im, since fifty is the largest amount Scripture ever names for an erech and no obligation can climb past it.
"Keitzad?" asks the mishnah: in what circumstances does this actually come up? The question deserves attention. If the pledger truly owns nothing at all, what is gained by informing him that a sela is due? And if a sela is in fact within his grasp, why must we be told? What halacha is this minimum coming to establish?
The sela that settles the debt
"Natan sela vehe'eshir."
Picture a pauper whose obligation the kohen reduced to one sela, which he duly handed over. Later his circumstances improved and he grew wealthy, easily able to produce the fifty sela'im his vow had originally called for (suppose he had pledged the erech of a male between twenty and sixty). Of him the mishnah rules "eino noten kelum": nothing further is owed. That single sela discharged the vow, and the file is closed.
"Pachot misela vehe'eshir, noten chamishim sela."
If, however, the most he could produce was some amount short of a sela, genuinely everything he had at that moment, and prosperity came to him afterward, the full fifty is now due. Why? Because nothing had ever been settled. A sum under a sela does not count toward an erech obligation whatsoever, so his liability was still standing when his fortune changed, and a man of means pays the erech of a man of means.
Here, then, is what the minimum teaches. The sela is not merely the least that will be collected; it is the least that qualifies as a payment at all.
Rabbi Meir and the chachamim: does anything lie in between?
"Haya beyadav chamesh sela'im."
A man liable for fifty sela'im has five in his possession.
Rabbi Meir's position is "eino noten ela achat": only one sela leaves his hand, notwithstanding the five he holds. Because the fifty lies beyond him he ranks as a poor pledger, and a poor pledger's figure is one sela. A principle stands behind this: once the Torah's amount is lowered at all, it drops the whole way down to a single sela, with no stopping points along the descent.
"Vachachamim omrim: noten et kulam."
In the view of the chachamim all five are handed over. The moment more than one sela lies within his ability, that is what he owes, even if the total matches neither the Torah's fifty nor the pauper's one. The choice is not between the full pledged figure and a solitary sela. He gives whatever is within his capacity.
The chachamim then restate the ruling with which the mishnah began: nothing beneath a sela, nothing beyond fifty. Their choice to phrase the halacha as a lower limit and an upper limit is instructive, because limits imply a whole range lying between them. And the fact that the mishnah lets the dispute close on their words suggests that the halacha is theirs: erech payments are not an all or nothing affair, and the sums in the middle are genuine.
The same formula, a new subject: niddah and zivah
Having supplied us with a "never less, never more" formulation in the laws of arachin, the mishnah transfers that identical wording to a completely different field.
When a woman experiences uterine bleeding she holds the status of niddah for seven days. Biblically no spotless days are demanded of her: whether the bleeding lasted a single day or ran the full seven, so long as it ceased before the seventh day was over she immerses in a mikveh once that seventh day ends, and she is tehorah.
The next eleven days are designated the days of zivah, and bleeding turns a woman into a zavah only when it falls inside them. Bleeding for one or two of those days makes her a zavah ketannah, who is shomeret yom keneged yom, observing one spotless day. Bleeding on three days in a row makes her a zavah gedolah, who must tally seven days entirely free of flow before immersing and attaining taharah.
From here comes the practice, instituted by the rabbis, whereby every woman counts seven spotless days without exception, out of standing concern that she might in truth be a zavah gedolah.
The cycle itself runs seven days and then eleven, eighteen days altogether. Once those eighteen are behind her, fresh bleeding starts the whole sequence over: a new stretch of seven niddah days, trailed once again by eleven days of zivah.
The woman who lost count
Our mishnah turns to a woman who bled but cannot tell where in the cycle she stands, inside her niddah days or inside the eleven days of zivah. Since a mitzvat de'oraita is at stake she must take the stricter path, regard herself as possibly a zavah, and count seven spotless days.
Yet more than the immediate stringency is at issue. She would like to break out of the doubt altogether, so that her next bleeding will carry a defined status and she is not left in permanent uncertainty. What she needs is a run of spotless days long enough for the sequence to restart on its own, guaranteeing that whatever bleeding follows is plainly the beginning of a new niddah period. Exactly how many such days that requires is what the mishnah now supplies.
"Ein petach batto'ah pachot mishiv'ah, velo yater al shiv'ah asar."
Petach means an opening, the clean start of a fresh niddah period. A woman thrown into doubt by losing her reckoning cannot arrive at such an opening on fewer than seven spotless days, and never requires more than seventeen. Which number applies to her depends on how long the bleeding she just had continued. Bleeding of one day leaves her needing seventeen spotless days to lift herself out of the doubt; bleeding that stretched over thirteen days leaves seven spotless days sufficient.
The same formula again: nega'im
The mishnah now brings the same wording to the tum'ah of tzara'at. A patch of discolored skin is called a nega, and the person carrying it is tamei and bears the name metzora. Tzara'at can also strike a house or an article of clothing, where the shades that convey tum'ah are red and green.
Discoloration on its own does not render a person, a dwelling or a garment tamei; corroborating signs are required. When the kohen inspects and finds no such signs, he shuts the matter up for seven days, holding the status in abeyance to see whether signs will develop. A week that passes with nothing to show brings a second week of confinement. Signs surfacing then produce a ruling of tum'ah. Should that second week also conclude with none, a human being is pronounced tahor, while clothing whose discoloration still remains is tamei, and a house that has yielded no signs is confined for one further week.
"Ein banega'im pachot mishavua echad."
No tzara'at confinement is ever shorter than one week. A nega that arises on the scar tissue left behind after a boil or a blister has healed is confined for a single week alone, and absent any signs the man is tahor.
At the upper end the mishnah rules that confinement never extends past "shelosha shavu'ot", three weeks, meaning that no case involves more than three separate periods of confinement. That maximum, as described above, belongs to the house.