This is again the second sign that Jesus did, having come out of Judea into Galilee.
"Both the miracles performed at Cana . . . are thus shown to have been prompted by trust. Mary trusted her Son to do something to relieve the embarrassment of their host at the wedding. The father of the sick boy was equally confident that he could rely on Jesus’ help. Both miracles are also shown to have resulted in a personal surrender to Jesus which is full Christian faith. His disciples believed on him after the water had been turned into wine; the father and the rest of his household believed as the result of the healing of the boy: and in both cases the verb in the original is an inceptive aorist ’they put their faith in Him’." [Note: Tasker, pp. 82-83.] 