וְאִ֗ישׁ אֲשֶׁ֥ר יִקַּ֛ח אֶת־אֵ֥שֶׁת אָחִ֖יו נִדָּ֣ה הִ֑וא עֶרְוַ֥ת אָחִ֛יו גִּלָּ֖ה עֲרִירִ֥ים יִהְיֽוּ׃
Seorang laki-laki yang mengambil istri saudara laki-lakinya, itu adalah perbuatan yang menjijikkan; ia telah menyingkapkan aurat saudaranya; mereka akan tetap tanpa anak.
Mishnah Zevachim
An unclean [person] who eats [of sacrifices], whether unclean sacrifices or clean sacrifices, is liable. Rabbi Yose the Galilean says: an unclean person who eats clean [sacrifices] is liable, but an unclean person who eats unclean [sacrifices] is not liable because he ate only that which is unclean. They said to him: even when an unclean person eats clean [sacrifices], when he touches it, he defiles it. A clean person who eats unclean [sacrifices] is not liable, because one is liable only on account of bodily uncleanness.
Mishnah Yevamot
Two sisters-in-law, one says, “My husband is dead”, and the other also says, “My husband is dead”, this one is forbidden on account of the husband of this one, and this one is forbidden on account of the husband of this one. If one had witnesses and the other had no witnesses, she who has the witnesses is forbidden, while she who has no witnesses is permitted. If the one has children and the other has no children, she who has children is permitted and she who has no children is forbidden. If they contracted yibbum, and the yevamim died, they are forbidden [to marry again]. Rabbi Elazar says: since they were permitted to marry the yevamim, they are subsequently permitted to marry any man.