If the man with the discharge touches anyone without first rinsing his hands with water, the one who was touched must wash his clothes and bathe with water, and he will be unclean until evening.
We have here the law concerning the ceremonial uncleanness that was contracted by running issues in men. It is called in the margin (Lev 15:2) the running of the reins: a very grievous and loathsome disease, which was, usually the effect and consequent of wantonness and uncleanness, and a dissolute course of life, filling men's bones with the sins of their youth, and leaving them...
Commenting on Leviticus 15:1-18
And whomsoever he toucheth that hath the issue,.... Not only he that touched him that had the issue, but whomsoever, and indeed whatsoever he touched, as the Targum of Jonathan, the Septuagint, and Arabic versions, were unclean; See Gill on Lev 15:4, and hath not rinsed his hands in water; which is to be understood, not of the man that is touched, but of him...
And whomsoever he toucheth - Here we find that the saliva, sitting on the same seat, lying on the same bed, riding on the same saddle, or simple contact, was sufficient to render the person unclean, meaning, possibly, in certain cases, to communicate the disorder; and it is well known that in all these ways the contagion of this disorder may be communicated.