What you are espousing is a unholy bifurcation of God's chosen people. There are not two separate bodies called "Israel" that are sealed separate bodies. There isn't a Old Testament Jewish Israel of God and then a New Testament Gentile Israel of God. Israel is one holy people of God. The Israel of God is not divided into 144,000 OC Israel, PLUS some Gentiles, for God has stated that there is neither Jew nor Greek, we are all "one" in Christ. Israel is all one body in Christ Jesus. But don't take my word for it, receive the witness of scripture.
Neither I, nor the Bible separates God's chosen people into two separate bodies since the advent of Christ coming to earth to save His sheep (Jew & Gentile). But we cannot deny there was a "first Covenant" according to Levitical Law as well as the New Covenant according to grace. The first Covenant according to Law, though applicable to ALL people, was primarily for the Jews.
The Bible defines Israel of God through two distinct Covenants. Belonging to true Israel of God has always been by grace through faith under both the Old and New Covenant. There was an Israel of God born under the Old Covenant which according to Law one must submit to Judaism to be numbered with the Old Covenant body called, Israel. Before the advent of Christ Israel of faith were a single flock with one King, the Shepherd ordained of Old who was to come. It wasn't until the advent of Christ' coming that we learn of "other sheep" who are not of the fold of Israel of Old, and the two becoming "
one fold, and one Shepherd", called "Israel of God."
John 10:14-16 (KJV) I am the good shepherd, and know my
sheep, and am known of mine. As the Father knoweth me, even so know I the Father: and
I lay down my life for the sheep. And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice; and there shall be one fold, and one shepherd.
Matthew 10:5-7 (KJV) These twelve Jesus sent forth, and commanded them, saying,
Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not: But go rather to the lost sheep of the house of Israel. And as ye go, preach, saying, The kingdom of heaven is at hand.
Luke 24:47 (KJV) And that repentance and
remission of sins should be preached in his name among all nations, beginning at Jerusalem.
Romans 9:23-24 (KJV) And that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory,
Even us, whom he hath called, not of the Jews only, but also of the Gentiles?
I don't disagree the 144,000 of all the tribes of the children are together with the innumerable multitude and the fullness of the One Covenant body since the advent of Christ. But those of Old came to the Messiah by grace through faith according to faithfulness to the Law. Those of the New Covenant come to the same Messiah, called Christ Jesus our Lord by grace through the faithfulness of Christ alone and power of His Spirit.
You're conflating two different visions John saw of heaven, one from before creation, and the other after the 144,000 saints of Old were sealed with the Spirit a spiritual body, living souls, faithful saints coming from the Old Covenant.
John is given this first vision of heaven, that is a view from eternity before creation. Read in context beginning with vs 1-5 John is shown the plan of redemption enacted in heaven between the triune Godhead. The Covenant of Redemption came about because the book of God with the names written therein of all who were ordained to eternal life was sealed and no man in heaven or earth was found worthy to open the book. John wept because he realized that if the book could not be opened to look and know who was to be eternally saved, then none who are ordained to be saved would be saved. Christ was given to know His sheep, calling them by name.
But then as John watches he sees in the midst of the throne "
a Lamb as it had been slain". The Lamb took the book from the hand of the Father, and all the hosts of heaven, with all the prayers of the saints sang a new song, no longer the song of Moses that was of Old when Israel was set free from captivity of Egypt. Now John hears a new song of the Lamb being slain He was worthy to open the Lamb's Book of Life that the redeemed written in the book would be redeemed by the blood of the Lamb.
Revelation 5:6-10 (KJV) And I beheld, and, lo, in the midst of the throne and of the four beasts, and in the midst of the elders, stood
a Lamb as it had been slain, having seven horns and seven eyes, which are the seven Spirits of God sent forth into all the earth. And he came and took the book out of the right hand of him that sat upon the throne. And when he had taken the book, the four beasts and four and twenty elders fell down before the Lamb, having every one of them harps, and golden vials full of odours, which are the prayers of saints. And they sung a new song, saying, Thou art worthy to take the book, and to open the seals thereof: for thou wast slain, and hast redeemed us to God by thy blood out of every kindred, and tongue, and people, and nation; And hast made us unto our God kings and priests: and we shall reign on the earth.
In this vision John sees a sea of glass, symbolizing all the saints of heaven, mingled with fire, symbolizing how they/we were must come through fiery trials/testing Christians throughout the ages are called to endure. Notice, not only are they singing the son of Moses, representing Christ, of Old Covenant saints, but also singing the New Covenant song of the Lamb, together representing the fullness of the Covenant body from both old and new together.
Revelation 15:2-4 (KJV) And
I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glass, having the harps of God. And they sing the song of Moses the servant of God, and the song of the Lamb, saying, Great and marvellous are thy works, Lord God Almighty; just and true are thy ways, thou King of saints. Who shall not fear thee, O Lord, and glorify thy name? for
thou only
art holy: for all nations shall come and worship before thee; for thy judgments are made manifest.
Revelation 13:8 (KJV) And all that dwell upon the earth shall worship him, whose names are not
written in the book of life of the Lamb slain from the foundation of the world.
Revelation 17:8 (KJV) The beast that thou sawest was, and is not; and shall ascend out of the bottomless pit, and go into perdition: and they that dwell on the earth shall wonder, whose names were not
written in the book of life from the foundation of the world, when they behold the beast that was, and is not, and yet is.
Luke 10:20 (KJV) Notwithstanding in this rejoice not, that the spirits are subject unto you; but
rather rejoice, because your names are written in heaven.
Revelation 20:12 (KJV) And I saw the dead, small and great, stand before God; and
the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
The vision John sees here symbolizes the 144,000 after being sealed a spiritual body/living souls who ascended with Christ to heaven after He arose from the grave. They sing a new song the song of the Lamb which only they were then privy to being the firstfruits of spiritual life, living souls in heaven who are as the angels of God spirit beings without human form.
Revelation 14:1-3 (KJV) And I looked, and, lo,
a Lamb stood on the mount Sion, and with him an hundred forty and four thousand, having his Father's name written in their foreheads. And I heard a voice from heaven, as the voice of many waters, and as the voice of a great thunder: and I heard the voice of harpers harping with their harps: And they sung as it were a new song before the throne, and before the four beasts, and the elders: and no man could learn that song but the hundred and forty and four thousand, which were redeemed from the earth.