Vayikra 20:18

18 And if an ish shall lie with an isha during her davah (menstruous unwellness), and shall uncover her nakedness, he hath made bare her mekor (source), and she hath uncovered the source of her dahm; and both of them shall be cut off from among their people.

Vayikra 20:18 Meaning and Commentary

Leviticus 20:18

And if a man shall lie with a woman having her sickness
Her monthly courses, which make her weak and languid, which is forbidden, ( Leviticus 18:19 ) ; this is not to be understood of a man's lying with his wife ignorantly, when in such a condition, for this being the case, he was only unclean seven days, ( Leviticus 15:24 ) ; whereas this made him and her liable to cutting off, as in an after clause; but of his lying with her, knowing this to be the case with her, and of which she could not be ignorant, and therefore both liable to the same punishment; or else of any other man lying with her, or of any man lying with any woman, married or unmarried, being in such circumstances: and shall uncover her nakedness;
that is, have carnal knowledge of her: he hath discovered her fountain;
from whence her issue of blood flows: and she hath uncovered the fountain of her blood; freely and willingly, as Aben Ezra observes; for if she had been forced, he alone would have been cut off; but both these phrases put together show agreement in this matter, that they both had knowledge of her case, and both consented to commit the sin: and both of them shall be cut off from among their people;
by death, either by the hand of the civil magistrate, the case being known and proved, or else by the hand of God being known by mortality or the pestilence, as the Targum of Jonathan, or they should die childless; (See Gill on Leviticus 20:17).

Vayikra 20:18 In-Context

16 And if an isha approach unto any behemah, and lie down thereto, thou shalt kill the isha, and the beast; they shall surely be put to death; their dahm shall be upon them.

17 And if an ish shall take his achot, the bat of his av (father), or the bat of his em (mother), and see her nakedness, and she see his nakedness; it is a disgrace; and they shall be cut off in the sight of their Bnei Am; he hath uncovered the nakedness of his achot (sister); he shall bear his iniquity.

18 And if an ish shall lie with an isha during her davah (menstruous unwellness), and shall uncover her nakedness, he hath made bare her mekor (source), and she hath uncovered the source of her dahm; and both of them shall be cut off from among their people.

19 And thou shalt not uncover the nakedness of thy mother’s achot (sister), nor of thy father’s achot (sister); for he uncovereth (i.e., incestuously dishonored) his near kin; they shall bear their iniquity.

20 And if an ish shall lie with the wife of his dod, he hath uncovered his uncle’s nakedness; they shall bear their chet; they shall die childless.