Matthew Henry on Leviticus 15:19–end
This is concerning the ceremonial uncleanness which women lay under from their issues, both those that were regular and healthful, and according to the course of nature (Lev 15:19-24), and those that were unseasonable, excessive, and the disease of the body; such was the bloody issue of that poor woman who was suddenly cured by touching the hem of Christ's garment, after she had lain twelve years under her distemper, and had spent her estate upon physicians and physic in vain. This made the woman that was afflicted with it unclean (Lev 15:25) and every thing she touched unclean, Lev 15:26, Lev 15:27. And if she was cured, and found by seven days' trial that she was perfectly free from her is…
Read the whole note in the consoleJamieson-Fausset-Brown on Leviticus 15:19
UNCLEANNESS OF WOMEN. (Lev 15:19-33)
if a woman have an issue--Though this, like the leprosy, might be a natural affection, it was anciently considered contagious and entailed a ceremonial defilement which typified a moral impurity. This ceremonial defilement had to be removed by an appointed method of ceremonial expiation, and the neglect of it subjected any one to the guilt of defiling the tabernacle, and to death as the penalty of profane temerity.
Adam Clarke on Leviticus 15:18
They shall both bathe themselves - What a wonderful tendency had these ordinances to prevent all excesses! The pains which such persons must take, the separations which they must observe, and the privations which, in consequence, they must be exposed to in the way of commerce, traffic, etc., would prevent them from making an unlawful use of lawful things.
John Gill on Leviticus 15:23
And if it be on her bed, or on anything whereon she sitteth,.... That is, if any person or thing should be upon her bed or seat; a vessel on her bed, or a vessel upon a vessel, as Aben Ezra expresses it:
when he toucheth it; that person or thing that should be on her bed or seat, as well as touch her bed or seat:
shall be unclean until the even; in a ceremonial sense; so defiling was a woman in such circumstances, and to whom the Scriptures often compare unclean persons and things: and Pliny (i) speaks of menstrues as very infectious, or worse, to various creatures and things, in a natural way.
(i) Nat. Hist. l. 7. c. 15.