In the interlude between the sixth seal and seventh seals, an angel in possession of "the seal of the living God", cries to four other angels to not harm the earth, the sea, nor the trees, until the servants of God have been sealed on their foreheads.
(2) And I saw another angel ascending from the rising of the sun, having the seal of the living God; and he cried out with a loud voice to the four angels to whom it was granted to harm the earth and the sea, (3) saying, "Do not harm the earth or the sea or the trees until we have sealed the bond-servants of our God on their foreheads." (4) And I heard the number of those who were sealed, one hundred and forty-four thousand sealed from every tribe of the sons of Israel (Revelation 7:2-4 NASB)
The controversy that has arisen from these verses regards the number and identity of people that John heard were to be sealed... 144,000 "from every tribe of the sons of Israel". The next four verses list 12,000 people from each of 12 named tribes... Judah, Reuben, Gad, Asher, Naphtali, Manasseh, Simeon, Levi, Issachar, Zebulun, Joseph, and Benjamin.
The Jehovah's Witnesses claim this literal number will come from their ranks, while others believe the 144,000 will be Jews who will be saved from the physical nation of Israel.
Scripture does not support either of these claims.
Literal Hereditary Jews?
There are several compelling reasons one cannot consider the 144,000 to be literal hereditary Jews.
1) Are we really supposed to believe that Jewish believers are protected while their Gentile brothers are left to perish, when the New Testament teaches that the middle wall of partition has been removed making both believing Jews and Gentile into one body and one building.and that all who believe in Christ are descendants of Abraham. The New Testament clearly teaches that Abraham was
".. the father of circumcision to those who not only are of the circumcision, but who also follow in the steps of the faith of our father Abraham which he had while uncircumcised. For the promise to Abraham or to his descendants that he would be heir of the world was not through the Law, but through the righteousness of faith. (Romans 4:12-13 NASB)
Paul also wrote...
Therefore, be sure that it is those who are of faith who are sons of Abraham. (Galatians 3:7 NASB)
remember that you were at that time separate from Christ, excluded from the commonwealth of Israel, and strangers to the covenants of promise, having no hope and without God in the world. But now in Christ Jesus you who formerly were far off have been brought near by the blood of Christ. For He Himself is our peace, who made both groups into one and broke down the barrier of the dividing wall... in whom the whole building, being fitted together, is growing into a holy temple in the Lord, in whom you also are being built together into a dwelling of God in the Spirit. (Ephesians 2:12-14 and 21-22 NASB)
2) Jesus' words to the disciples in Matthew 19:28 makes it very unlikely that the 12 tribes are to be considered literally.
And Jesus said to them, "Truly I say to you, that you who have followed Me, in the regeneration when the Son of Man will sit on His glorious throne, you also shall sit upon twelve thrones, judging the twelve tribes of Israel". (Matthew 19:28 NASB)
While it is true that in Moses' time, twelve men, one from each tribe ("each of whom was of his father's household") were the leaders of Israel (Numbers 1:44), Jesus had to be speaking figuratively because the twelve disciples did not belong to twelve separate tribes... Peter and Andrew were brothers, as were James and John.
3) Since the names of the 12 tribes are clearly listed (Judah, Reuben, Gad, Asher, Naphtali, Manasseh, Simeon, Levi, Issachar, Zebulun, Joseph, and Benjamin), a literal interpretation of this verse would mean that anyone who was not a member of these particular tribes would be left out. This would include Abraham, Isaac, and Jacob, who lived much before the tribes of Israel ever existed thuse did not belong to any of them. Additionally, the tribes of Ephraim and Dan are not on the list, which means that Joshua (Ephraim) and Samson from the tribe of Dan (Judges 13) will also be excluded.
And, of course, all Gentiles (non-Jews) are out. Yet, Jesus said... "I say to you that many will come from east and west, and recline at the table with Abraham, Isaac and Jacob in the kingdom of heaven" (Matthew 8:11 NASB)
Given all of the above, we cannot possibly believe that the 144,000 "sealed out of every tribe of the children of Israel" are anything but a spiritual representation of the "holy nation" of believers.
Literal Or Symbolic Number?
There are two choices here... the number 144,000 and the description of this group, is either literal or symbolic. The very number 144,000 is the number of the twelve tribes of Israel... squared (12 x 12) then multiplied by 1000, which certainly indicates symbolism.
One had better hope that this is true since Scripture tells us that these people are the only ones protected from God's wrath during the Great Tribulation. However, as discussed earlier, Scripture makes it clear that no believer is going to be the target of God's wrath.
Then out of the smoke came locusts upon the earth, and power was given them, as the scorpions of the earth have power. They were told not to hurt the grass of the earth, nor any green thing, nor any tree, but only the men who do not have the seal of God on their foreheads. (Revelation 9:3-4 NASB)
See The End of The Age
The prophet Joel also mentions this protection in the time of God's wrath, saying..
The sun and moon grow dark and the stars lose their brightness. The Lord roars from Zion And utters His voice from Jerusalem, And the heavens and the earth tremble. But the Lord is a refuge for His people And a stronghold to the sons of Israel. (Joel 3:15-16 NASB)
(Additionally, 2 Corinthians 1:22 talks of God establishing, anointing and sealing us, while Ephesians 1:13-14 combines sealing with redemption).
Those who are 'sealed', or have the name of the Father "written on their foreheads" (Revelation 14:1), will not be touched during the Great Tribulation, but the others, who have the 'Mark of The Beast' on their foreheads will suffer the full extent of the wrath of God.
(9) Then another angel, a third one, followed them, saying with a loud voice, "If anyone worships the beast and his image, and receives a mark on his forehead or on his hand, (10) he also will drink of the wine of the wrath of God, which is mixed in full strength in the cup of His anger; and he will be tormented with fire and brimstone in the presence of the holy angels and in the presence of the Lamb. (11) "And the smoke of their torment goes up forever and ever; they have no rest day and night, those who worship the beast and his image, and whoever receives the mark of his name." (Revelation 14:9-11 NASB)
In any case, the entire scene is symbolic... the angels holding the four winds, the great multitude arrayed in white robes, and the sealing itself, which is reminiscent of another occasion when the foreheads of men obedient to the Law were marked, or symbolically 'sealed'.
The Lord said to him, "Go through the midst of the city, even through the midst of Jerusalem, and put a mark on the foreheads of the men who sigh and groan over all the abominations which are being committed in its midst." But to the others He said in my hearing, "Go through the city after him and strike; do not let your eye have pity and do not spare. "Utterly slay old men, young men, maidens, little children, and women, but do not touch any man on whom is the mark; and you shall start from My sanctuary." So they started with the elders who were before the temple. (Ezekiel 9:4-6 NASB)
(See Mark of The Beast)
Physically or Spiritually Chaste?
In a later chapter of Revelation, these hundred forty and four thousand, who have the name of the Father on their foreheads, are depicted as standing on Mt. Zion with Christ.
(1) Then I looked, and behold, the Lamb was standing on Mount Zion, and with Him one hundred and forty-four thousand, having His name and the name of His Father written on their foreheads. (2) And I heard a voice from heaven, like the sound of many waters and like the sound of loud thunder, and the voice which I heard was like the sound of harpists playing on their harps. (3) And they *sang a new song before the throne and before the four living creatures and the elders; and no one could learn the song except the one hundred and forty-four thousand who had been purchased from the earth. (4) These are the ones who have not been defiled with women, for they have kept themselves chaste. These are the ones who follow the Lamb wherever He goes. These have been purchased from among men as first fruits to God and to the Lamb. (5) And no lie was found in their mouth; they are blameless. (Revelation 14:1-5 NASB)
What is confusing about the above verses is these people are said to have "not been defiled with women", but "kept themselves chaste", which can carry one of two meanings... a) They are either physically celibate (see Matthew 19:21) or b) they are spiritually faithful.
In the Old Testament, unfaithfulness to the Father was spoken of as prostitution or adultery...
for you shall not worship any other god, for the LORD, whose name is Jealous, is a jealous God-- otherwise you might make a covenant with the inhabitants of the land and they would play the harlot with their gods and sacrifice to their gods, and someone might invite you to eat of his sacrifice, and you might take some of his daughters for your sons, and his daughters might play the harlot with their gods and cause your sons also to play the harlot with their gods. (Exodus 34:14-16 NASB)
"Be strong and courageous, do not be afraid or tremble at them, for the LORD your God is the one who goes with you. He will not fail you or forsake you." (Deuteronomy 31:6 NASB)
How the faithful city has become a harlot, She who was full of justice! Righteousness once lodged in her, But now murderers. (Isaiah 1:21 NASB)
Surely, as a woman treacherously departs from her lover, So you have dealt treacherously with Me, O house of Israel," declares the LORD. (Jeremiah 3:20 NASB)
Do not rejoice, O Israel, with exultation like the nations! For you have played the harlot, forsaking your God. You have loved harlots' earnings on every threshing floor. (Hosea 9:1 NASB)
In the New Testament, the church is known as the "bride" of the Lamb (Revelation 19:7). The context of Paul's words in 2 Corinthians 11:2 ..."For I am jealous for you with a godly jealousy; for I betrothed you to one husband, so that to Christ I might present you as a pure virgin" (NASB) simply meant that believers would not be tainted by a "different gospel", but would stay faithful to the true Gospel which they had already heard from the apostles.
It seems quite clear that the entire largely corrupt, greedy, and/or power hungry, world system, both religious and commercial, is personified in Revelation 17 and 18. The 'Great City' spoken of in both chapters is not a literal city, but a figurative description of two systems... a religious system is outlined in chapter 17, and a political/commercial system is described in chapter 18. Dealing, as they do, with specific targets of the wrath of God, these chapters are a crucial, and unambiguous, warning to God's people, or anyone who has an ear to listen. The warning is ....
I heard another voice from heaven, saying, "Come out of her, my people, so that you will not participate in her sins and receive of her plagues; for her sins have piled up as high as heaven, and God has remembered her iniquities. (Revelation 18:4-5 NASB)
And, the 144,000 have done just that... escaped all spiritual defilement by distancing themselves from our materialistic, godless system that has grown fat at the expense of many, the 'harlotry' of embracing of false gods and man made religions, and the apostate church. As J. Hampton Keathley, III says...
This view fits with the following words, “these are those who follow the Lamb wherever He goes.” The whole group has remained devoted and faithful to the Lord Jesus Christ; they follow and serve Him as obedient servants in contrast to a world that as a whole goes whoring after the beast. 
Note: Religious "Babylon" is a spiritual kingdom, that reached back to Shinar and the tower of Babel, then physically and/or spiritually persisted in the physical kingdom of Babylon, and other nations as diverse as Egypt, Assyria, Greece, and Rome, all of whom wreaked havoc on Israel. This kingdom, the antitheses of Jerusalem, is alive and well, and still endeavors to carry away captives and win the battle. And, until finally defeated, it will extend it's tentacles into the future when spiritual apostasy and pure unmitigated evil will peak under the regime of the beast. See Two Babylons www.inplainsite.org/html/two_babylons.html
 J. Hampton Keathley, III. Special Announcements (Rev 14:1-20. https://bible.org/seriespage/20-special-announcements-rev-141-20