What does Luke 17:12 mean?

Jesus is somewhere near the border between Galilee and Samaria, making His way to Jerusalem and the cross (Luke 17:11). Although Jesus seems to be performing fewer miracles, He still has compassion to heal when the occasion arises.

Many Bible studies make a point of noting that the skin disease often translated as "leprosy" in the Bible is not always the same as the condition identified by that modern term. Literal leprosy is also called Hansen's disease. In fact, what the Bible depicts was probably an entire category of infections including "swelling or an eruption or a spot" (Leviticus 13:1) or an itch that turns hair yellow; "leprosy" can even appear on fabric (Leviticus 13:47).

Priests were responsible for identifying leprosy as well as declaring someone cured from the disease. Victims were to tear their clothes, let their hair fall loose, cover their upper lip, and yell, "Unclean, unclean." They were to avoid healthy people and live outside the "camp" (see Leviticus 13). That law was given when the Israelites were traveling. At the time this incident occurs, the people have a different understanding of what separation is necessary.

By the time of Jesus, it seems victims of leprosy live together. Extra-biblical writings suggest a leper is allowed to go into a village but not a city that has a wall and gate. They especially are not to enter Jerusalem. One of the greatest tragedies of leprosy is that victims were not allowed to worship at the temple; they wer separated from people and from corporate worship of their God. Because of the Old Testament's strong rules about ceremonial cleanliness, such persons were cut off from an important aspect of their own culture. These men have the courtesy to stand back even as they hope Jesus will heal them.