43 Now after two days he departed thence, and went into Galilee.

[Went into Galilee] Jesus continued the journey which he began at the beginning of the chapter.

44 For Jesus himself testified, that a prophet hath no honour in his own country.

[A prophet hath no honor in his own country] See Matthew 13:53-58 for an interesting example of this truth. It appears that on this journey Jesus may have bypassed, or at least not stayed long, at his hometown, Nazareth, as he travelled to the coast of Galilee.

45 Then when he was come into Galilee, the Galilaeans received him, having seen all the things that he did at Jerusalem at the feast: for they also went unto the feast.

[Cana of Galilee, where he made the water wine] Cana was on the road from Nazareth to Capernaum

[A certain nobleman] An officer of the king's court, for such is the meaning of the original word which may also be translated, "A little King". This officer belonged to Herod Antipas, who was then the tetrarch of Galilee. When he heard that Jesus was in Galilee he went to Cana to entreat Jesus to heal his child.

48 Then said Jesus unto him, Except ye see signs and wonders, ye will not believe.

[Except ye see signs and wonders] Our Lord did not tell this man that he had no faith, for if he had none he would not have come from Capernaum to Cana to beg him to heal his son. Jesus addressed these words to all of the Galilean Jews in general, for he used the plural, which he never would if addressing an individual.
These people differed widely from the people of Sychar (see the previous two commentaries): they had neither a love of truth nor simplicity of heart and would not believe anything from heaven unless forced on their minds by the most striking of miracles. There are many like these Galileans in the world; since they are not astonished daily by what they perceive to be miracles, they, in the genuine Galilean spirit, assume that, "God is dead" or is no longer relevant.

49 The nobleman saith unto him, Sir, come down ere my child die.

50 Jesus saith unto him, Go thy way; thy son liveth. And the man believed the word that Jesus had spoken unto him, and he went his way.

[Go thy way, thy son liveth] Had our Lord gone with him as he wished, his unbelief would not have been fully removed as he would have still thought that our Lord's power could not reach from Cana to Capernaum. In order to destroy his unbelief and bring him into the fullness of faith in his surpeme power, he cures him, being apparently absent, by the energy through which he fills the heavens and the earth.
Here it may be observed, our blessed Lord did what this man requested him to, but not in the way in which he wished it to be done. God will save to the uttermost all who call upon him. Eternal life is the free gift of God, purchased by Jesus' substitutionary death in our place on the cross, yet, as much of today's popular religious music will attest, many are unwilling to call upon God and give themselves over to being born anew by the Spirit of God. They wish to continue life just as they are and hope that in the end God will prove weak-willed and say, "Aww, you weren't that bad. Come on in and enjoy heaven with me." How tragically misinformed!

[And the man believed] His understanding may not have been perfect, but he had faith in what Jesus said and he acted upon it.

51 And as he was now going down, his servants met him, and told him, saying, Thy son liveth.
52 Then enquired he of them the hour when he began to amend. And they said unto him, Yesterday at the seventh hour the fever left him.

[Then inquired he of them the hour] The servants, overjoyed to find their master's son so suddenly restored, set off to meet him, that they might tell him what they knew would be so pleasing, and he, intent on having his faith verified, began immediately to inquire what time it was when the fever left him, to see whether his cure was the effect of some natural cause or whether it was done by the power of Christ.

53 So the father knew that it was at the same hour, in the which Jesus said unto him, Thy son liveth: and himself believed, and his whole house.

[So the father knew] He had the fullest proof that his son's cure was supernatural and that it was wrought by Christ.

[Himself believed, and his whole house.] He and his whole family became true converts to the doctrine of the manifested Messiah. They, no doubt, at first thought God was dealing hardly with them when threatening to remove the child, but now they see that in very faithfulness God had afflicted them. The sickness of the child became the means of salvation to the whole household.
Let us learn never to murmur against God or think that he does not act kindly toward us.

54 This is again the second miracle that Jesus did, when he was come out of Judaea into Galilee.

[The second miracle] The first miracle which Christ performed in Cana was just after his baptism, this second miracle in Cana took place when he returned from his trip to Jerusalem.