"Now it happened as [Jesus] went to Jerusalem that He passed through the midst of Samaria and Galilee. Then as He entered a certain village, there met Him ten men who were lepers, who stood afar off. And they lifted up their voices and said, 'Jesus, Master, have mercy on us!' So when He saw them, He said to them, 'Go, show yourselves to the priests.' And so it was that as they went, they were cleansed. And one of them, when he saw that he was healed, returned, and with a loud voice glorified God, and fell down on his face at His feet, giving Him thanks. And he was a Samaritan. So Jesus answered and said, 'Were there not ten cleansed? But where are the nine? Were there not any found who returned to give glory to God except this foreigner?' And He said to him, 'Arise, go your way. Your faith has made you well'" (Luke 17:11-19).
In this unknown village that Jesus entered there were ten lepers "who stood afar off." The law required lepers to keep away from the rest of the people to prevent their affliction from spreading (cf. Lev. 13:45,46). Leprosy was a most dreadful and terrible disease (though now it can be cured with medicine). It starts with sores and then slowly eats away at the body. In some cases, one's nose and lips will disappear, decaying fingers fall off, and joint after joint separates. Finally, the vital organs cease to function and death follows.
Evidently, these lepers had heard of Jesus and were aware of His power to heal. They pleaded with Him as their "Master" to "have mercy" on them. Considering their physical condition, their request would be understood by all.
"Go, show yourselves to the priests" (Luke 17:14). Jesus' ears were always open to the cries of the distressed. They made their request with a certain degree of faith and here Jesus tests their faith by issuing this command. A leper, according to the law, when cured was to show himself to the priest (cf. Lev. 14). The priest would make the determination as to whether or not the leper was healed.
"And so it was that as they went, they were cleansed." Their faith was tested in that they were not healed immediately when Jesus told them to go to the priest. But, as they obeyed, they were cleansed (cf. James 2:24,26). It is not known how far they went before they were healed (evidently not so far that the Samaritan couldn't return and find Jesus easily).
We learn from Luke 17:15 that this man returned and glorified God with a "loud voice." Surely he spoke loudly because of his gratitude which he expressed excitedly. This man realizes the value of the wonderful gift he has just received (cf. II Kings 5:15). The man was so overjoyed that he fell down on his face at Jesus' feet and gave thanks.
Jesus then asked - "But where are the nine?" (Luke 17:17). The ones who did not return had stood the test of faith, but they failed in the test of thanksgiving. Sadly, many today follow the example of the nine. They are more ready to ask for blessings than to thank God for the ones they receive and enjoy.
Giving thanks to God is equated with giving Him glory (cf. Luke 17:18). The wording here leads us to the conclusion that the other nine lepers were Jews. Ironically, the one who would be considered by most to be the least likely to give thanks was the one who did! Ordinarily the Jews had no dealings with the Samaritans, but the common affliction of the lepers had drawn these ten men together. Notice that Jesus was happy to heal a Samaritan and that the Samaritan wasn't bothered by speaking to a Jew. These two men didn't let the social norms of that day hinder them from doing good or giving thanks.
"Your faith has made you well" - Jesus emphasizes the fact that this blessing was made possible because of the man's faith. Certainly He was encouraging the man to seek spiritual blessings by the same means.