To continue with Isaiah 9:6-7
A related Scripture is Isaiah 7:10 Moreover the Lord spoke again to Ahaz, saying,
11 “Ask a sign for yourself from the Lord your God; ask it either in the depth or in the height above.”
12 But Ahaz said, “I will not ask, nor will I test the Lord!”
13 Then He said, “Hear now, O house of David! Is it a small thing for you to weary men, but will you weary my God also?
14 Therefore the Lord Himself will give you a sign: Behold, the virgin shall conceive and bear a Son, and shall call His name Immanuel.
This statement from Isaiah 9:6, refers to Christ, Immanuel, --- “And the government will be upon His shoulder.”
9:7 “Of the increase of His government and peace There will be no end, Upon the throne of David and over His kingdom, To order it and establish it with judgment and justice From that time forward, even forever.”
--- Notice this in Daniel 7:13 “I was watching in the night visions, And behold, One like the Son of Man, Coming with the clouds of heaven!
He came to the Ancient of Days, And they brought Him near before Him.
14 Then to Him was given dominion and glory and a kingdom, That all peoples, nations, and languages should serve Him. His dominion is an everlasting dominion, Which shall not pass away, And His kingdom the one Which shall not be destroyed.
--- This Son of Man is Christ, who is called the Son of Man in the Gospels.
Also, in Luke 1:30 Then the angel said to her, “Do not be afraid, Mary, for you have found favor with God. 31 And behold, you will conceive in your womb and bring forth a Son, and shall call His name Jesus. 32 He will be great, and will be called the Son of the Highest; --- and the Lord God will give Him the throne of His father David. 33 And He will reign over the house of Jacob forever, and of His kingdom there will be no end.”
--- From the semi colon after Highest, it refers to Christ, Immanuel, who was given the kingdom.
And in 1 Corinthians 15:22 “For as in Adam all die, even so in Christ all shall be made alive. 23 But each one in his own order: Christ the firstfruits, afterward those who are Christ’s at His coming. 24 Then comes the end, when He delivers the kingdom to God the Father, when He puts an end to all rule and all authority and power. 25 For He must reign till He has put all enemies under His feet. 28 Now when all things are made subject to Him, then the Son (of Man) Himself will also be subject to Him who put all things under Him, that God may be all in all.
--- From the sign given to Ahaz to this last line, it fulfils the redemptive plan, and returns the kingdoms of this world to God, as the verse says in 2 Corinthians 5:19
“That God was in Christ, reconciling the world unto Himself.”
--- And the last line of Isaiah 9:7 “The zeal of the Lord of hosts will perform this.”
Blessings