[Isa 9:6 NLT] (6) For a child is born to us, a son is given to us. The government will rest on his shoulders. And he will be called: Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.
This is actually a mistranslation.
First of all, let me point out that traditional Christianity, aka Trinitarianism, likes to quote this verse, which is clearly Messianic, to say that the Messiah will be the Father (Almighty God). However, true Judaism and true Christianity are fiercely monotheistic. That is, while many are called “gods” in the scripture, there is always a sharp distinction between these heroes who are referred to as “gods” and such (as in the same name above) and God, the Father, the Almighty. This passage is not meant to blur that line.
The correct translation and significance is something more like “Father of Innumerable [Children]”:
It is the word in the following verse for David’s innumerable troubles:
[Psa 40:12 NLT] (12) For troubles surround me--too many to count! My sins pile up so high I can't see my way out. They outnumber the hairs on my head. I have lost all courage.
This becomes more obvious in the next verse:
[Isa 9:7 NASB] (7) There will be no end to the increase of [His] government or of peace, On the throne of David and over his kingdom, To establish it and to uphold it with justice and righteousness From then on and forevermore. The zeal of the LORD of hosts will accomplish this.
This is how, of course, the promise to Abraham is brought to fruition:
[Gen 15:5-6 NLT] (5) Then the LORD took Abram outside and said to him, "Look up into the sky and count the stars if you can. That's how many descendants you will have!" (6) And Abram believed the LORD, and the LORD counted him as righteous because of his faith.
We see the continuously increasing and uncountable number of descendants in Revelation:
[Rev 7:9-12 NASB] (9) After these things I looked, and behold, a great multitude which no one could count, from every nation and [all] tribes and peoples and tongues, standing before the throne and before the Lamb, clothed in white robes, and palm branches [were] in their hands; (10) and they cry out with a loud voice, saying, "Salvation to our God who sits on the throne, and to the Lamb." (11) And all the angels were standing around the throne and [around] the elders and the four living creatures; and they fell on their faces before the throne and worshiped God, (12) saying, "Amen, blessing and glory and wisdom and thanksgiving and honor and power and might, [be] to our God forever and ever. Amen."
The 144,000 in the previous section are the chosen remnant of the lost sheep of the house of Israel, living and dead, reunited with faithful Jews from Judah into the “one stick” of the united kingdom of Israel, under the one shepherd, the Messiah/Christ per Ezekiel 37. These that come after are the ever growing Christians from all nations, including Israel, living and dead, and composed of both Jews and gentiles. They are the first fruits. They have a different origin story than those that follow but other than that, they are one covenant people along with the ever increasing number that comes after:
[Eph 4:4-6 NLT] (4) For there is one body and one Spirit, just as you have been called to one glorious hope for the future. (5) There is one Lord, one faith, one baptism, (6) and one God and Father, who is over all and in all and living through all.
The ones in the first group were an elect remnant, chosen by God and their number is given. The ones that follow are innumerable because their numbers keep growing forever. They are as uncountable as the stars in the sky and as the sand of the sea. In fact, they are described, not as you see in English translations, those who “came out” but rather “are coming out of the great trouble”. It is a present continuous, ongoing reality.
The NASB has modified this by adding an inappropriate comma and adding the word “they” which obscures this so I’ve taken the liberty of putting both in brackets below:
[Rev 7:13-17 NASB] (13) Then one of the elders answered, saying to me, "These who are clothed in the white robes, who are they, and where have they come from?" (14) I said to him, "My lord, you know." And he said to me, "These are the ones who come [better: "are coming"] out of the great tribulation[,] and [they] have washed their robes and made them white in the blood of the Lamb. (15) "For this reason, they are before the throne of God; and they serve Him day and night in His temple; and He who sits on the throne will spread His tabernacle over them. (16) "They will hunger no longer, nor thirst anymore; nor will the sun beat down on them, nor any heat; (17) for the Lamb in the center of the throne will be their shepherd, and will guide them to springs of the water of life; and God will wipe every tear from their eyes."
The Jehovah’s Witnesses organization claims falsely to be the 144,000 and royalty which is patently false. They also claim that the 144,000 have a different hope. This is somewhat true in that in that they were the ones who were to be raptured in order to join Jesus when he returned c. 70 AD/CE to judge the living and the dead of Israel:
[Jde 1:14-15 NASB] (14) [It was] also about these men [that] Enoch, [in] the seventh [generation] from Adam, prophesied, saying, "Behold, the Lord came with many thousands of His holy ones, (15) to execute judgment upon all, and to convict all the ungodly of all their ungodly deeds which they have done in an ungodly way, and of all the harsh things which ungodly sinners have spoken against Him."
The “armies of heaven” are these elect 144,000:
[Rev 19:14-15 NLT] (14) The armies of heaven, dressed in the finest of pure white linen, followed him on white horses. (15) From his mouth came a sharp sword to strike down the nations. He will rule them with an iron rod. He will release the fierce wrath of God, the Almighty, like juice flowing from a winepress.
[Eze 37:10-14 NLT] (10) So I spoke the message as he commanded me, and breath came into their bodies. They all came to life and stood up on their feet--a great army. (11) Then he said to me, "Son of man, these bones represent the people of Israel. They are saying, 'We have become old, dry bones--all hope is gone. Our nation is finished.' (12) Therefore, prophesy to them and say, 'This is what the Sovereign LORD says: O my people, I will open your graves of exile and cause you to rise again. Then I will bring you back to the land of Israel. (13) When this happens, O my people, you will know that I am the LORD. (14) I will put my Spirit in you, and you will live again and return home to your own land. Then you will know that I, the LORD, have spoken, and I have done what I said. Yes, the LORD has spoken!'"
However, afterwards there is but one flock, one shepherd, one hope, which is the hope of everlasting life together with Christ, wherever he is.