John Gill's Exposition of the Whole Bible
Leviticus 20:11
And the man that lieth with his father's wife,.... Whether she be his mother, or another woman, as the Targum of Jonathan; that is, whether she is his own mother, or a stepmother, or whether he did this in the lifetime of his father, or after his death, or whether she was betrothed or married, it mattered not; according to the Jewish tradition d, this is a breach of the law, Leviticus 18:8; and a man guilty of this
hath uncovered his father's nakedness; and which is a foul and shameful piece of wickedness; the penalty follows:
both of them shall be put to death; by casting stones on them, as the Targum of Jonathan adds; for, as before observed, wherever the following phrase,
their blood [shall be] upon them, is used, stoning is meant; and so, according to the Misnah e, all those were to be stoned, after mentioned, of whom this phrase is used.
d Misn. ut supra, (Sanhedrin, c. 7.) sect. 4. e lbid.