Leviticus 15:2

“Speak unto the children of Israel, etc.] From whence we learn, says the above mentioned writer, that these uncleannesses were only usual among the children of Israel, not among the Gentiles; that is, the laws respecting them were only binding on the one, and not on the other f519: and say unto them, when any man; in the Hebrew text it is, “a man, a man”, which the Targum of Jonathan paraphrases, a young man, and an old man: hath a running issue out of his flesh; what physicians call a “gonorrhoea”, and we, as in the margin of our Bibles, “the running of the reins”: [because of] his issue, he [is] unclean; in a ceremonial sense, though it arises from a natural cause; but if not from any…”

“A running issue - Commonly called the running of the reins, a grievous and loathsome disease, which is generally the consequence of sin. Leviticus 15:3”

“15:2 bodily discharge (literally a flowing from his flesh): Most scholars interpret the word flesh as a euphemism for sexual organs and the symptoms described here as indicating an infection of gonorrhea. Others suggest that it refers to a discharge of semen or even diarrhea. A discharge of semen is unlikely, however, because that is singled out in 15:16-17 and required only washing with water. It is clear that this bodily discharge proceeded from “under the man” (15:10) and contaminated anything he sat on or lay upon (15:4, 6, 9).”

“unto the: Deu 4:7, Deu 4:8; Neh 9:13, Neh 9:14; Psa 78:5, Psa 147:19, Psa 147:20; Rom 3:2 when any man: It is not necessary to consider particularly the laws contained in this chapter, the letter of the text being in general sufficiently plain. It may, however, be observed, that from the pains which persons rendered unclean were obliged to take, the ablutions and separations which they must observe, and the privations to which they must in consequence be exposed, in the way of commerce, traffic, etc., these laws were admirably adapted to prevent contagion of every kind, by keeping the whole from the diseased, and to hinder licentious indulgences and excesses of every description. Lev 22:4;…”

“The running issue from a man is not described with sufficient clearness for us to be able to determine with certainty what disease is referred to: "if a man becomes flowing out of his flesh, he is unclean in his flux." That even here the term flesh is not a euphemism for the organ of generation, as is frequently assumed, is evident from Lev 15:13, "he shall wash his clothes and bathe his flesh in water," when compared with Lev 16:23-24, Lev 16:28, etc., where flesh cannot possibly have any such meaning. The "flesh" is the body as in Lev 15:7, "whoever touches the flesh of him that hath the issue," as compared with Lev 15:19, "whosoever toucheth her." At the same time, the agreement between…”