Arachin, Chapter 4, Mishnah 4. The mishnah just before this one set down four principles that operate when someone pledges the arachin sum attached to somebody else, and it went on to clarify only the first of them. Our mishnah presents the three that remain, and then confronts a difficulty that grows out of the Torah's own division of life into four age brackets: where does a person belong when he is standing precisely on the boundary between one bracket and the next?
The second law: whose years do we count?
"Shanim banidar." When we clarify which age category determines the sum to be paid, we measure by the nidar, the person who is the subject of the vow, and not by the age of the one who opened his mouth and made the vow.
"Keitzad?" How so? "Yeled shehe'erich et hazaken" - a young fellow who declared the erech of an elderly man - "noten erech zaken": the sum he owes is the one listed for the aged, because the years being counted are those of the man he spoke about. And the reverse holds as well: "vezaken shehe'erich et hayeled" - an elderly man who declared the erech of a child - "noten erech hayeled": he pays the figure listed for a child.
The third law: whose gender do we follow?
"Va'arachin bane'erach." The arachin table sets one figure for a male and another for a female, and here too we look at the person being vowed about, not at the one making the vow.
"Keitzad? Ish shehe'erich et ha'ishah, noten erech ishah." Should a man pledge a woman's arachin, what he owes is the amount fixed for a female. "Ve'ishah shehe'erichah et ha'ish, notenet erech ish." And should a woman pledge a man's arachin, she owes the amount fixed for a male.
The fourth law: which moment do we freeze?
"Veha'erech bizman ha'erech." The sum is set by the subject's age at the moment the vow was pronounced, and not by his age at the moment the money is actually handed over.
"Keitzad? He'ericho pachot miben chamesh, vena'asah yoter al ben chamesh." Someone pledged the erech of a child who had not yet completed five years, and by the time the money changed hands that child was already past five. So too: "pachot miben esrim, vena'asah yoter al ben esrim" - when the vow was uttered the subject had not yet completed twenty, and by the time of payment he had gone beyond twenty. "Noten bizman ha'erech." What he owes is fixed by the bracket that applied on the day he spoke; whatever age the subject has reached by the day the money is delivered makes no difference at all.
Standing on the line
The Torah gives us four age brackets: one month until five years, five until twenty, twenty until sixty, and above sixty. What, then, of a person who is precisely at the seam: the thirtieth day of life, the fifth year, the twentieth year, the sixtieth year? Does he belong to the younger bracket or to the older one?
"Yom sheloshim kilmatah mimenu." An infant on the thirtieth day of his life is treated, for arachin, as younger than thirty days. The first bracket begins at one month, and on day thirty the month is not yet complete, so he has not yet entered it; the number must be fully passed.
"Shenat chamesh ushnat esrim kilmatah mimenah." Someone in the course of his fifth year, or in the course of his twentieth, is classified as still being beneath those ages. His fifth year has not carried him out of his first five, and his twentieth has not carried him out of his first twenty. Work through the count: from birth to one, one to two, two to three, three to four, four to five. A child in the middle of that fifth year is, in ordinary speech, a four year old, though the year he is living through is his fifth; and if a person pledges his arachin, the amount owed is the one set for the bracket that runs from one month to five. Precisely the same holds for someone in the middle of his twentieth year.
Learning it from the sixtieth year
The source is the pasuk: "Ve'im miben shishim shanah vama'alah, im zachar." "And if from sixty years of age and above, if it is a male," then the erech is such and such. The oldest bracket is defined as those above sixty, from which it follows that a person who is in his sixtieth year is still counted with the younger group.
The Torah says nothing explicit about the other transitional points, the thirtieth day, the fifth year and the twentieth year. Still: "harei anu lemedim bekulam mishnat shishim." We derive all of them from the sixtieth year. "Mah shenat shishim kilmatah mimenah, af shenat chamesh ushenat esrim kilmatah mimenah." Just as one in his sixtieth year is reckoned as below sixty, so one in his thirtieth day, his fifth year or his twentieth year is reckoned as below those ages.
But is the comparison sound?
The mishnah now presses on its own derivation. "Hen" - granted, but does the argument really hold? "Im asah shenat shishim kilmatah mimenah lehachmir." In the case of sixty, ruling that the man in his sixtieth year is below sixty produces a stringency: one above sixty has a lower erech than one below sixty, so keeping him in the younger bracket obligates him in the larger sum.
"Na'aseh shenat chamesh ushenat esrim kilmatah mimenah lehakel?" Shall we then also place the one in his fifth year or twentieth year in the lower bracket, when there the result is a leniency? In the three younger transitions the older bracket carries the higher figure, so assigning him downward means less money is paid. Perhaps, then, the sixtieth year teaches nothing about them at all: there the lower bracket costs more, while here the lower bracket costs less, and the two situations are not comparable.
The gezeirah shavah
"Talmud lomar: 'shanah shanah' ligezeirah shavah." The Torah writes the word "shanah" by the sixtieth year and the word "shanah" by the fifth and the twentieth year, and that shared word ties the cases together. "Mah shanah ha'amurah bishnat shishim kilmatah mimenah, af shanah ha'amurah bishnat chamesh ushenat esrim kilmatah mimenah." Just as the "shanah" stated at sixty places the man in his sixtieth year below his age, so the "shanah" stated at five and at twenty places a person below those ages.
From this gezeirah shavah we learn that the fifth, twentieth and sixtieth years all belong to the younger bracket, "bein lehakel bein lehachmir": whether the outcome is lenient, as in the fifth and twentieth years, where treating him as younger yields the smaller payment, or stringent, as in the sixtieth year, where treating him as under sixty yields the larger payment rather than the reduced sum of one above sixty.
Rabbi Elazar's view
"Rabbi Elazar omer." Rabbi Elazar maintains that someone in his fifth, twentieth or sixtieth year is not moved into the higher bracket even once the birthday itself has come and gone. He stays where he was "ad sheyihyu yeterot al hashanim" - until his age exceeds the stated number by "chodesh veyom echad," a month and a day. On his view, then, a person is still reckoned within the bracket of five to twenty for a full month and a day after his twentieth birthday has passed.