17:14 Go shew yourselves. To be officially pronounced clean, a certificate had to be obtained from the priests (see PNT Mt 8:4 ).
They were cleansed. As they went, an act of faith, they were healed. Not one would have been healed if he had disobeyed.
17:11-19 A sense of our spiritual leprosy should make us very humble whenever we draw near to Christ. It is enough to refer ourselves to the compassions of Christ, for they fail not. We may look for God to meet us with mercy, when we are found in the way of obedience. Only one of those who were healed returned to give thanks. It becomes us, like him, to be very humble in thanksgivings, as well as in prayers. Christ noticed the one who thus distinguished himself, he was a Samaritan. The others only got the outward cure, he alone got the spiritual blessing.