In general, the Mishnah tends to be terse — offering short statements of positions — and the Gemara lengthy and discursive. Not so today. The mishnah on today’s page takes up nearly half the daf, and the full breadth is well beyond the scope of this essay, but let’s take a look at the opening just to get a taste.
Rabban Gamliel says: A bill of divorce is not effective after a bill of divorce. And levirate betrothal is not effective after a previous levirate betrothal. And intercourse is not effective after intercourse. And halitzah is not effective after halitzah. But the rabbis say: A bill of divorce is effective after a bill of divorce, and levirate betrothal is effective after levirate betrothal, but nothing is effective after intercourse or after halitzah.
What on earth are we talking about here? Why would someone give one bill of divorce and then another one? Or perform levirate betrothal or halitzah once, and then do it again?
We know that if a man dies childless, his surviving brother has the option of either marrying his brother’s widow (yibbum) or not, in which case he performs halitzah. But let’s say instead, the surviving brother delivers a bill of divorce, or a get. What then?
As we have seen, the levirate bond has legal strength — akin to, but not identical to, a marriage. So even though tendering a divorce is not the correct procedure, one can see why the yavam might be tempted to take that route.
Rabban Gamliel apparently wasn’t sure whether a get was effective at severing the levirate bond, since that possibility isn’t provided for in the Torah. If it is effective, then the first one works and the man has effectively nullified his levirate obligation. Any get he gives subsequently has no legal significance. This is true whether we’re talking about oneyavamand one yevama — if the man gave the woman an effective get, a second one would be meaningless. And it would be true if there were one yavam and two yevamot — the first get nullifies the levirate bond for both the woman who received it and the second one who didn’t, rendering the second get meaningless. And it would be true for two yevamim and one yevama — the first get nullifies the bond with the woman for both brothers, so a second get would also have no significance.
But what if the first get is not effective at severing the levirate bond? In that case, neither would the second one. In either case, a get after a get is not effective.
Still with me? Good, because we’re barely scratching the surface here.
A similar logic holds for Rabban Gamliel’s three subsequent rulings. If a man performed levirate betrothal with his brother’s wife, a second betrothal (either with the same woman or a second wife) is of no legal significance, since one man can only perform yibbum with one wife (or with one woman one time). Likewise, if he had sex with the woman and thereby consummated the levirate marriage with her, having sex with her again would have no legal significance and likewise with her co-wife, since a man is barred from performing yibbum with two co-wives. And finally, if he performed halitzah, a second halitzah (either with the same woman or with her co-wife) would be legally meaningless, since the first halitzah severs the levirate bond to the woman with whom he performs it and all her co-wives.
The rabbis partially disagree with Rabban Gamliel. Regarding a get, the rabbis held that since it’s not one of the two options prescribed by the Torah after a man dies childless, it doesn’t carry the same legal force as halitzah in severing the levirate bond. The man may still have some biblical basis for wedding the second wife, which can similarly be (somewhat) nullified by the second get. Same with levirate betrothal, but not with sex or halitzah.
The mishnah goes on — and on. Why did the rabbis need to spend so much time on these potential scenarios? It’s clear not everyone either knew or interpreted Torah the way the rabbis did. So while the rabbis held that a man should either perform yibbum or halitzah with his dead brother’s wife (or one of his wives), that’s clearly not the way things always worked out. Sometimes people — out of ignorance or a different interpretation of Jewish law — took a third route and gave a get. Or they betrothed both wives, even though that’s not allowed. Or had sex with both women (ditto).
One is tempted to think that given how much ink the rabbis have spilled these last 50 pages figuring out the complicated rules of levirate marriage (and all the seemingly infinite permutations resulting therefrom) as it is supposed to happen, they’ve ensured everything works just according to plan. But that’s not the real world. Some people don’t know the laws (especially when they’re this complicated), and some don’t care. And some may have held a different interpretation. Any good legal system must prepare for these contingencies because in real life, things don’t always go by the book — even the good book.
Read all of Yevamot 50 on Sefaria.