Citation: Luke 17:11-19, unique to Luke.
Narrative
As Jesus travels toward Jerusalem, passing between Samaria and Galilee, ten lepers meet him. Keeping their distance (as the law required), they lift their voices: "Jesus, Master, have mercy on us!" Jesus says, "Go, show yourselves to the priests." And as they went, they were cleansed.
One of them, seeing that he was healed, turns back, glorifying God with a loud voice, and falls on his face at Jesus' feet, giving him thanks, "and he was a Samaritan." Jesus asks, "Weren’t the ten cleansed? But where are the nine? Were there none found who returned to give glory to God, except this foreigner?" Then to the man: "Get up, and go your way. Your faith has healed you."
Theological significance
Gratitude, and its rarity. Ten are cleansed; one returns. The story is Luke's pointed lesson on thankfulness: the gift received without the Giver acknowledged is the common human default; gratitude that returns to God is the exception.
The Samaritan, again. As with the [Good Samaritan], Luke makes the despised outsider, the half-breed heretic in Jewish eyes, the one who gets it right, shaming the nine (presumably Jewish) who do not return. It is a recurring Lukan reversal: grace lands first on those written off.
Cleansed versus made whole. All ten are "cleansed" (their leprosy is gone). But to the one who returns, Jesus says something more, "your faith has made you well" (sesōken se, "has saved you"). The nine received the cure; the one received, through faith and worship, a deeper wholeness. Note that this distinction (healing vs. salvation) is a real interpretive emphasis, while some read the phrase simply as confirming the cure.
Obedience before evidence. The ten are healed not at Jesus' touch but "as they went", they are cleansed in the act of obeying a command whose result they could not yet see.
Theological framing (multiple views)
Traditions agree the parable-like miracle teaches gratitude and faith, with Luke's characteristic spotlight on the outsider. The cleansed-vs-saved nuance is variously stressed (the Samaritan alone received salvation, not only healing) or downplayed (the phrase recognizes the same cure). Both are presented here and neither is forced.