At this time I'd like to begin sharing ten truths pertaining to leprosy, and, in so doing, note some parallels between it and sin.
1. Leprosy appears to be harmless at first, and so does sin.
Leviticus 13:2 - "When a man has on the skin of his body a swelling, a scab, or a bright spot, and it becomes on the skin of his body like a leprous sore, then he shall be brought to Aaron the priest or to one of his sons the priests." What might appear to be insignificant at first could actually be something quite serious, like leprosy. Such is often the case with temptation and sin. What begins as something small or seemingly insignificant (i.e., something that we perceive to be just slightly removed from the pathway of righteousness) can quickly degrade into something much more serious. For example, what begins as lust in one's heart may develop into fornication. Illicit thoughts may seem rather trivial to some, but if such thoughts are quickly squashed, fornication would cease to exist. Sin is deceptive and destructive (cf. Rom. 7:11). The wise will flee from it and not consider it lightly, no matter how harmless it may appear at first.
2. Leprosy is primarily an individual problem, and so is sin.
As Leviticus 13:2 indicates, leprosy is a matter that must be dealt with on an individual level. The individual had the responsibility to go to the priest for an examination of the sore in his flesh. Sin is also primarily an individual problem, as Ezekiel 18:20 indicates - "The soul who sins shall die. The son shall not bear the guilt of the father, nor the father bear the guilt of the son. The righteousness of the righteous shall be upon himself and the wickedness of the wicked shall be upon himself." Although it is true that others are affected by the consequences of my sins, they are not accountable for my transgressions. The same is true with leprosy. Under the Old Law, those who knew a leper were to avoid him. Thus, his leprosy had consequences on others, but the responsibility for the problem was primarily his.
3. Leprosy causes a person to be unclean, and so does sin.
Leviticus 13:3 records - "The priest shall examine the sore on the skin of the body; and if the hair on the sore has turned white, and the sore appears to be deeper than the skin of his body, it is a leprous sore. Then the priest shall examine him, and pronounce him unclean." As long as a man had leprous skin, he was unclean. Likewise, as long as a person is living in sin, he is unclean, spiritually speaking. Consider Ephesians 5:3-5 - "But fornication and all uncleanness or covetousness, let it not even be named among you, as is fitting for saints; neither filthiness, nor foolish talking, nor coarse jesting, which are not fitting, but rather giving of thanks. For this you know, that no fornicator, unclean person, nor covetous man, who is an idolater, has any inheritance in the kingdom of Christ and God." Sin must be repented of before God can forgive it and cleanse the individual (cf. Acts 2:38).
We will contemplate some more of these parallels in our next lesson.