וְאִ֗ישׁ אֲשֶׁ֥ר יִקַּ֛ח אֶת־אֵ֥שֶׁת אָחִ֖יו נִדָּ֣ה הִ֑וא עֶרְוַ֥ת אָחִ֛יו גִּלָּ֖ה עֲרִירִ֥ים יִהְיֽוּ׃
And if a man shall take his brother’s wife, it is impurity: he hath uncovered his brother’s nakedness; they shall be childless.
Read halakhic rulings (Jewish law) on Leviticus 20:21: and classical halakhic sources.