. [If there were] three brothers, [and] two of them were married to two sisters, while one was married to a stranger; [if] the husband of one of the sisters died, and the one married to the stranger married his wife, and the wife of the second one [then] died, and then the one married to the stranger died —- she is forbidden to him forever, since she was once forbidden to him.  [If there were] three brothers, [and] two of them were married to two sisters, while one was married to a stranger; [if] the husband of one of the sisters divorced his wife, and [then] the one [who was] married to the stranger died, and the divorced [brother] married her and [then] died —- about this it was said: If any of them died or were divorced, their co-wives are permitted.

. If any of them had been the subject of a questionable betrothal or divorce, the co-wives require chalitzah but may not be taken in yibum. How is it that the betrothal was in question? [If] he threw the betrothal to her, and there is a doubt as to whether it was closer to him or closer to her —- this is a questionable betrothal. [How is it that] the divorce was in question? [If] he wrote [a bill of divorce] in his own hand but without witnesses, or with witnesses but without a date, or with a date but with only one witness —- this is a questionable divorce.

[If] three brothers were married to three strangers and one of them died, and [then] the second performed maamar with her and [also] died —- they require chalitzah, but may not be taken in yibum, as it is stated (Deut. 25:5): “. . . and one of them dies . . . her husband's brother shall come to her” —- [only a widow] who is attached by one brother's bond [is subject to yibum], not [a widow] who is attached by two brothers' bonds. R' Shimon says: He may perform yibum with whichever one he wishes, but he must [then] perform chalitzah with the other.  [If] two brothers were married to two sisters, and one of them died, and then the second one's wife died —- she is forbidden to him forever, because she was once forbidden to him.

Two [men] who betrothed two women, but when they entered the bridal canopy they confused one with the other —- they are obligated [to bring a sin-offering] because of adultery; if they were brothers —- because of [the prohibition against] a brother's wife; if they were sisters —- because of [the prohibition against] a wife's sister; if they were menstruants —- because of [the prohibition against] a menstruant. We separate them for three months in case they are pregnant; but if they were minors incapable of childbirth, we restore them immediately. If they were the daughters of Kohanim, they are disqualified from [eating] terumah.