You shall not uncover the nakedness of your brother’s wife; it is your brother’s nakedness.
16. Thou shalt not uncover the nakedness of thy brother’s wife. They are bad In Willet this exposition is attributed to Radulph., Blesensis, and Borrhaus. interpreters who raise a controversy on this passage, and expound it, that a brother’s wife must not be taken from his bed, or, if she be divorced, that manage with her would be unlawful whilst her husband was still alive...
These laws relate to the seventh commandment, and, no doubt, are obligatory on us under the gospel, for they are consonant to the very light and law of nature: one of the articles, that of a man's having his father's wife, the apostle speaks of as a sin not so much as named among the Gentiles, Co1 5:1.
Commenting on Leviticus 18:6-18
Thou shalt not uncover the nakedness of thy brother's wife,.... Neither debauch her nor after the death of the brother marry her, that is, unless he dies without issue; and then, by another law, he was obliged to marry her, Deu 25:5; hence the Targum of Jonathan adds; by way of explanation."in the life of thy brother, or after his death, if he has children,''but...