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 ^F4, 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 ^F5, all those were to be stoned, after mentioned, of whom this phrase is used.