13 Then how great and how divine are the words reported to have been spoken with Nicodemus! From these the evangelist proceeds again to the testimony of John, and brings before our notice the fact, that the friend of the bridegroom cannot but rejoice because of the bridegroom's voice. In this statement He gives us to understand that the soul of man neither has light derivable from itself, nor can have blessing, except by participation in the unchangeable wisdom. Thereafter he carries us on to the case of the woman of Samaria, in connection with which mention is made of the water, whereof if a man drinks, he shall never thirst again.
Once more, he brings us again to Cana of Galilee, where Jesus had made the water wine. In that narrative he tells us how He spoke to the nobleman, whose son was sick, in these terms: “Unless you see signs and wonders ye believe not:” in which saying He aims at lifting the mind of the believer high above all things mutable, so that He would not have even the miracles themselves, which, however they may bear the impression of what is divine, are yet wrought in the instance of what is changeable in bodies, made objects of seeking on the part of the faithful.
Source: The Harmony of the Gospels (New Advent)