Leprosy in the Bible
The biblical instructions for leprosy, the separation, isolation, and cleansing of the leper and thus the biblical foundation as a picture of sin are described for us in Leviticus 13-14. The Hebrew word for leprosy, x`r^A^T, was actually used of a wider range of skin diseases as well as what is today called leprosy or Hansen’s disease caused by the bacillus mycobacterium leprae. The Greek word is lepra from lepw which means, “to peel off in scales.” It is equivalent to psoriasis, only it was far more serious than the psoriasis we think of today. Scholars are somewhat in disagreement regarding biblical leprosy, but it appears that there were two main types. “The first, and by far the more dangerous, is called lepromatous; and the other, a more benign type, is designated as tuberculoid . . . Both start with discoloration of a patch of skin. This patch may be white or pink. It is most likely to appear on the brow, nose, ear, cheek or chin.”46
(1) The Lepromatous Type: As this form begins to spread, portions of the eyebrow may disappear, then spongy tumor like swellings appear on the face and body. The disease is systemic and involves the internal organs as well. It is deep seated in the bones, joints and marrow of the body resulting in the deterioration of the tissues between the bones. The results are deformity, loss of feeling in the appendages, and in the fingers and toes eventually falling off. This form is incurable and lasts until the victim finally dies often by the invasion of other diseases because of the weakened condition. They may live for twenty or thirty years in this miserable condition.47
(2) The Tuberculoid Type: This form is less severe and begins much like the lepromatous form with a change in skin color in one area and then spreading to other areas. This form is limited in its effects and often only lasts from one to three years. The person with this form, unless miraculously healed, could return to the priest and be declared cleansed or healed after observation. Other types of skin diseases were observed and when found not be to true leprosy or they disappeared, the people with these forms were also declared clean. Other than by God’s direct intervention, it appears the Hebrews had no cure for leprosy. In modern times there are very effective medicines available, and leprosy patients are usually not isolated.48
One thing is certain, the term leprosy referred to several types of skin diseases which were rooted in the blood stream. When they were the lepromatous type, they were incurable and led to horrible consequences. Because of this, specific directions were given for leprosy in Leviticus 13-14. This was done first as a protection against possible spread in case it was contagious, but there was also a ceremonial or spiritual reason. Leprosy stood as a picture of sin and all its features and effects upon man and upon his relationship with God.
(1) The leper was considered unclean and had to be isolated from society to a certain degree. Wherever he went he was to cry out, “unclean, unclean,” and he had to wear black with a hood covering his face and live outside the city walls.
(2) Whenever the Lord Jesus healed a leper he always pronounced the person, not healed, but cleansed.
(3) True leprosy was incurable by man in Bible times just as sin is incurable for man (Jer. 17:9, “desperately sick,” “beyond cure” or “incurably sick”; see also Isa. 1:5-6). There is nothing man himself can do to deal with his sin problem. Further, his sin separates him from God and even from intimate fellowship with people (cf. 1 Cor. 5:9-13; 2 Cor. 6:14-7:1). When the Lord healed a leper, therefore, the picture should have been obvious. His power to cleanse a leper demonstrated He was the solution to man’s sin and defilement; He alone was and is the means of reconciliation, peace with God and man.
(4) The rite of purification in the Old Testament did not cure, it only recognized the fact a leper was cured, he was clean of the disease, or that he never really had the incurable type of leprosy. He could then be reconciled to society.
(5) Leprosy, like sin, begins within (with what we are) and then erupts on the skin (on the surface). As such, it clearly reminds us of the principle that men are, by an inherited nature, sinners and that it’s not just what we do that is so bad, but what we are. The point is the mouth speaks and hands do as a result of what the heart is and thinks (Luke 6:43-45; Ps. 51:5; 58:3; Matt. 12:33-34; Eph. 2:1f). With this in mind, compare Leviticus 13:1-4. Even the slightest blemish in the skin, a swelling (a boil), a scab (a small tumor), or a bright spot (a red or scaly place) was to be carefully observed to see if it was the product of something deeper, i.e., some form of true leprosy.
(6) The priest was to examine the skin and pronounce the person clean or unclean depending upon his observation of the facts. So today, since Christ has provided cleansing from sin, every believer as a believer priest is to detect sin in their own life and pronounce it sin when it first appears (1 John 1:8-10).49
(7) The pain of leprosy, at least in certain forms, was not acute because it also killed the nerves in the affected area, but it kept the victim restless, miserable, and frustrated as they felt the stigma of the disease. They saw portions of their bodies become numb, muscles atrophy (waste away), tendons contract making the hands like claws, and then the ulceration of the fingers and toes and hands and feet resulting in their loss bit by bit until the whole hand or foot was gone. We must not miss the picture God wants us to see from this emphasis in Scripture. Sin is like this. Because of man’s separation from God, because of his spiritually dead condition and the hardness of his soul, he becomes insensitive, callused, restless and never satisfied. He often does not experience severe pain from his sin and waywardness, only insensitivity, restless misery, and futility, ever seeking some means of fulfillment running from one thing to another (cf. Isa. 57:20-21; Eph. 4:16-19). Even in apparent prosperity and happiness, not only is there a certain amount of inner peace and true happiness missing, but their ultimate plight is death, loss, and the judgment of separation (Ps. 1:4-5; 73:1-28).
(8) Because of the nature of the disease, the leper was often considered as dead; it was a kind of living death though physically alive. So men without Christ are nothing more than the living dead; though walking about they are spiritual zombies (Eph. 2:1).
(9) Regardless of one’s position, honor, power, possessions, or wealth, leprosy, like sin, is no respecter of persons. Naaman was a man of position and prestige, but he was also leprous.
(10) As seen previously, in Israel, according to the Law, lepers were excluded from society as a picture of sin and its effects. God used this to remind Israel of His holiness. Cleansing a leper meant being restored back to a normal life. The term “cure” in 2 Kings 5:3 literally meant, “to receive back.” This provides us with a fitting picture of our reconciliation to God and to one another (cf. Isa. 59:2 with 2 Cor. 5:18-21).
(11) Finally, the leprosy of sin destroys the pleasantness and beauty God meant for mankind in His creation. Sin deforms us, but in Christ we are made new creations and can be transformed into His glorious likeness (2 Cor. 5:17; Rom. 12:1-2; Gal. 4:19). See also 2 Kings 5:14.
The above section is from: http://bible.org/seriespage/healing-naaman-2-kings-51-19
Leviticus 14:42 And they shall take other stones, and put them in the place of those stones; and he shall take other morter, and shall plaister the house.
The above section is from: http://www.bible-topics.com/Leprosy.html