Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
Leviticus Chapter 15
Other cases connected with the weakness of nature are mentioned, but which point out that, sin having come in, all that is of nature, of the flesh, defiles (whatever may be the excuse as to the weakness and the unavoidable character of the thing). If it cannot be avoided, it is the manifestation, or at least the inevitable existence, of that which is shameful, because it is a nature fallen and sinful. We shall find, however, that, though being shameful, the case is supposed less morally serious than leprosy. In leprosy there was the manifestation of positive corruption, existing beforehand in the nature, which was admitted in the heart, so that a long process was necessary to purify the conscience. Here they only washed once, and they offered merely a sin-offering, and they were thereby able, in offering their burnt-offering, to enter into communion through the sweet savour of Christ.