Addressing the OP, only. after reading a few post, which many are very good posts. not saying that any are right or wrong, but consider this
The sealing of the elect, the firstfruit of the whole house of Israel, the 144,000
Revelation 7:1 "And after these things I saw four angels standing on the four corners of the earth, holding the four winds of the earth, that the wind should not blow on the earth, nor on the sea, nor on any tree.
After these things, (the previous seal), But what and who are the the four “winds?” well there’s a difference between the four winds of Heaven and the four winds of the earth. here, the four winds of the EARTH are the four fallen angles that are bound in the great river Euphrates, (see Revelation 9:14). that's in contrast to the four winds of HEAVEN.
so, before the seventh seal is open, meaning a world wide judgment which is about to happen, it is put on paused by God. Why the pause? because of a world wide fulfillment, Matthew 24:31 "And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.” that’s why for the pause. For the elect or the “Firstfruit” of the whole house of Israel is sealed also. What do we mean by “Firstfruit” here? not of the Dead but of the living in spiritual restoration. Supportive scriptures, Romans 16:5 "Likewise greet the church that is in their house. Salute my wellbeloved Epaenetus, who is the firstfruits of Achaia unto Christ”. and 1 Corinthians 16:15 "I beseech you, brethren, (ye know the house of Stephanas, that it is the firstfruits of Achaia, and that they have addicted themselves to the ministry of the saints,). did one notice the (s) at the end of each word “Firstfruits”. meaning more to come.
Question, "how do we know that these, 144,000 are the Firstfruits of the whole house of Israel? To understand that, we need to go to chapter 14. Revelation 14:1 "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. (These are the same one’s in Chapter 7). verse 2 "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: verse 3 "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. verse 4 "These are they which were not defiled with women; for they are virgins. These are they which follow the Lamb whithersoever he goeth. These were redeemed from among men, being the firstfruits unto God and to the Lamb”. BINGO, now we know that these 144,000 are the “Firstfruits” unto God and christ. note this, THEY WAS STANDING, SIGNIFYING, "VICTORY", meaning that they also has OVERCOME, “IN” him, Christ Jesus, who STANDS/OVERCOME. and one other thing, these virgins, are not males, (ONLY), but is of the church, 2 Corinthians 11:2 "For I am jealous over you with godly jealousy: for I have espoused you to one husband, that I may present you as a chaste virgin to Christ”.
REMEMBER, Revelation is signified, so contrary to popular belief, NO, they are not all male virgins, (for in christ neither are male nor female). I know many believed that when they read, “were not defiled with women”, NO, it’s meaning that they was not defiled with false doctrine, as was with the scarlet… “WOMAN”. now one other thing, these 144,000 follow the Lamb, (the Spirit), supportive Scripture, Romans 8:1 "There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit. Verse 2 "For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death. Verse 3 "For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh: Verse 4 "That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit”. (BINGO, they follow the Spirit, the Lamb).
The Mount here is not an actual mountain, but it Signify the church, (mount Zion), which is the GREAT Mountian, (again remember Revelation is signified). and as before, these 144,000 is just the firstfruit of many to come. (for John heard the number, but not the set number). a small number in comparison of such as should be amoung the coming harvest. how do we know this, listen to Revelation 7:9 "After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands;" BINGO, so the 144,000 was only the "first fruit" of many to come, (the church).
PICJAG.
PS,
“having his Father's name written in their foreheads” this is their open profession of being the children and servants of God. 1 Timothy 6:12 "Fight the good fight of faith, lay hold on eternal life, whereunto thou art also called, and hast professed a good profession before many witnesses”. Hebrews 10:23 "Let us hold fast the profession of our faith without wavering; (for he is faithful that promised”.