עֶרְוַ֥ת אֵֽשֶׁת־אָחִ֖יךָ לֹ֣א תְגַלֵּ֑ה עֶרְוַ֥ת אָחִ֖יךָ הִֽוא׃ (ס)
너는 형제의 아내의 하체를 범치 말라 이는 네 형제의 하체니라
Genesis
Therefore, a man shall leave his father and his mother, and cling to his wife, and they shall become one flesh.
Deuteronomy
If brothers reside together, and one of them dies having no son, let the wife of the dead man not marry outside [the family] to a strange man; her brother-in-law will consummate with her thus marrying her to be his wife, and perform levirate marriage with her.