‘And it came about that, as they were on the way to Jerusalem, he was passing along the borders of Samaria and Galilee.'
When Luke gives a detailed introduction he regularly has a purpose in it. Thus the mention of being on the way to Jerusalem brings the shadow of His death over the narrative. It is as the One Who is going to bear the sins of many, and to bear our sicknesses and diseases, that He can heal these men.
As we have observed earlier Jesus making of His way to Jerusalem to die is not just a straightforward journey. Having been in the environs of Jerusalem twice He is now going along the border between Galilee and Samaria. This explains the presence of a Samaritan among the skin diseased men who are the subject of the passage. But Luke probably intends also by his presence to imply that the journey to Jerusalem will have effects that will go beyond Judaism. It is because He is on His way to die in Jerusalem that His journey takes Him to a position where He is midway between Samaria and Galilee, for that death will break the barriers between them.
‘On the way to Jerusalem' has a sombre note to it. It is all part of His set purpose and expectancy to die in Jerusalem. This is indeed why He can offer cleansing.