It wasn’t until God raised up Louis Pasteur in the 1850s to discovered “germs.” As the head of the science department, he discovered the long process of matching bacteria with a specific disease. Today we drink pasteurized milk and enjoy long lives. For the 1800’s years, the church didn’t have the benefit of germ theory. Today, we know one specific germ causes one specific disease.
In Luke 5, Jesus heals a leprous man. Like Elijah and Elisha, Jesus heals lepers. Unfortunately, most lepers were not healed nor were most widows fed (cf. Luke 4:24-26).
What did leprosy signify?
If we don’t see an overt link between the disease and our lives, most of us don’t connect sickness with sin. Later in Luke 17, Jesus heals ten lepers. Thomas Aquinas preaches a sermon on why there were ten lepers that helps connect leprosy (sin) and different kinds of sins.
Thomas Aquinas links the 10 lepers with 10 specific sins (“spiritual germs”):
- The first leper is an infidel and a heretic who is separated from the society of the faithful and the holy: “The Lord spake unto Moses, saying, Command the children of Israel, that they put out of the camp every leper … and the children of Israel did so, and put them without the camp,” (cf. 5:24)
- The second leper is a blasphemer and detractor: “And Miriam and Aaron spake against Moses because of the Ethiopean woman whom he had married … and they said, Hath the Lord spoken only by Moses? Hath He not also spoken by us? And the Lord heard it.… Wherefore, then, were ye not afraid to speak against My servant Moses?.… And Aaron looked upon Miriam, and behold she was leprous,” Num. 12:1, 2, 8, 10.
- The third leper is gluttonous, who taints the air with fetid exhalations, proceeding from excessive repletion: “He is a leprous man, he is unclean.… He shall put a covering upon his upper lip, and shall cry, Unclean, unclean,” Levit. 13:44, 45.
- The fourth leper is the avaricious man, who is ever infected with an immoderate desire of possessing: this was the leprosy of Gehazi: “Is it a time to receive money, and to receive garments, and oliveyards … the leprosy therefore of Naaman shall cleave unto thee, and unto thy seed for ever,” 2 Kings 5:26, 27.
- The fifth leper is the proud man, who with a swelling mind exalts himself against the Lord and Christ. Such was Naaman, King of Syria, and being very rich, and “also a mighty man in valour, but he was a leper,” 2 Kings 5:1.
- The sixth leper is the ambitious man, who desired honours and dignities: such an one as Uzziah, who took upon himself the honour of High Priest: “He transgressed against the Lord his God, and went into the temple of the Lord to burn incense … and while he was wroth with the priests the leprosy rose up in his forehead before the priests,” 2 Chron. 26:16–20. (7)
- The seventh leper is the hypocrite or vainglorious, who foolishly prides himself on his good things: such was the leprosy of Simon the Pharisee: “When Jesus was in Bethany in the house of Simon the leper,” S. Matt. 26:6.
- The eighth leper is the sensual man, who contaminates creatures with the issue of his uncleannesses: “What man so ever of the seed of Aaron is a leper, or hath a running issue, he shall not eat of the holy things until he be clean,” Levit. 22:3.
- The ninth leper is a homicide: such as was Joab, upon whom the wrath of God came because he slew Abner: “Let there not fail from the house of Joab one that hath an issue, or that is a leper,” 2 Sam. 3:29.
- The tenth leper is he who is obstinate and desperate, and who finally sins: “When the plague of leprosy is in a man … if the rising be white in the skin, and it have turned the hair white.… it is an old leprosy,” Levit. 13:9–11.
Aquinas concludes with a quote from Jerome: “He who despairs of pardon for sin is more bound by his desperation than by the sin which he has committed. Desperation increases despair, and is a greater tyrant than any sin. He who wishes to be cured from sin’s leprosy runs to the fountain of precious blood, which the ineffable charity of our Lord Jesus Christ opened for us: Who washed us in it, and will cleanse all those who fly unto Him from the leprosy of all sin. “Unto Him that loved us and washed us from our sins in His own blood … to Him be glory and dominion forever and ever. Amen.” Rev. 1:5, 6.
Before my next checkup, or grab that pill from the medicine cabinet, I might want to consider making my slate is clean before God.
 Ashley, J. M. (1866). Homily XXVIII: The Ten Lepers: Fourteenth Sunday after Trinity.—(From the Gospel). In J. M. Ashley (Trans.), Ninety-Nine Homilies of S. Thomas Aquinas upon the Epistles and Gospels for Forty-Nine Sundays of the Christian Year (Vol. 4, pp. 49–50). London: Church Press Company.