Why was Jesus called the King of the Jews and the King of Israel?

Quick references;

King of Jews (KJV)

Matt.2

1. [2] Saying, Where is he that is born King of the Jews? for we have seen his star in the east, and are come to worship him.

Matt.27

1. [11] And Jesus stood before the governor: and the governor asked him, saying, Art thou the King of the Jews? And Jesus said unto him, Thou sayest.
2. [29] And when they had platted a crown of thorns, they put it upon his head, and a reed in his right hand: and they bowed the knee before him, and mocked him, saying, Hail, King of the Jews!
3. [37] And set up over his head his accusation written, THIS IS JESUS THE KING OF THE JEWS.

Mark.15

1. [2] And Pilate asked him, Art thou the King of the Jews? And he answering said unto him, Thou sayest it.
2. [9] But Pilate answered them, saying, Will ye that I release unto you the King of the Jews?
3. [12] And Pilate answered and said again unto them, What will ye then that I shall do unto him whom ye call the King of the Jews?
4. [18] And began to salute him, Hail, King of the Jews!
5. [26] And the superscription of his accusation was written over, THE KING OF THE JEWS.

Luke.23

1. [3] And Pilate asked him, saying, Art thou the King of the Jews? And he answered him and said, Thou sayest it.
2. [37] And saying, If thou be the king of the Jews, save thyself.
3. [38] And a superscription also was written over him in letters of Greek, and Latin, and Hebrew, THIS IS THE KING OF THE JEWS.

John.18

1. [33] Then Pilate entered into the judgment hall again, and called Jesus, and said unto him, Art thou the King of the Jews?
2. [39] But ye have a custom, that I should release unto you one at the passover: will ye therefore that I release unto you the King of the Jews?

John.19

1. [3] And said, Hail, King of the Jews! and they smote him with their hands.
2. [19] And Pilate wrote a title, and put it on the cross. And the writing was, JESUS OF NAZARETH THE KING OF THE JEWS.
3. [21] Then said the chief priests of the Jews to Pilate, Write not, The King of the Jews; but that he said, I am King of the Jews.

King of Israel (KJV)

Matt.27

1. [9] Then was fulfilled that which was spoken by Jeremy the prophet, saying, And they took the thirty pieces of silver, the price of him that was valued, whom they of the children of Israel did value;
2. [42] He saved others; himself he cannot save. If he be the King of Israel, let him now come down from the cross, and we will believe him.

Mark.15

1. [32] Let Christ the King of Israel descend now from the cross, that we may see and believe. And they that were crucified with him reviled him.

John.12

1. [13] Took branches of palm trees, and went forth to meet him, and cried, Hosanna: Blessed is the King of Israel that cometh in the name of the Lord.
   

Answer

The terms 'Jew' and 'Israel' are entirely synonymous in the context as they are merely different names for the same people. Different writers used these interchangeable terms at different times as it suited them, with no particular significance in mind, as quoted above.

First answer by Itchie.c2. Last edit by PeteNco. Contributor trust: 296 [recommend contributor]. Question popularity: 24 [recommend question]