This is again the second sign that Jesus did, having come out of Judea into Galilee.
The evident purpose of including this wonder in the list of seven was to show that the physical presence of the Lord was not required in the performance of his signs, but that his holy will was effective from any distance whatever.  Such a miracle as this is never even attempted by modern claimants of miraculous power; and yet, why not?  If one can do it at all, the distance is not a factor.  Why must one enter the tent, or the studio, stand in line, and wait for the healer to wave his hand or jerk his head?  This second sign placed Jesus our Lord in a category beyond all human imitations.