The 5th seal is about God's people desiring justice. The answer is the 6th seal (as you said). Yet, while God purifies this Earth of evil by fire after Christ's return (2 Peter 3:10), that does not mean sin will not exist in the Millennium or that the remaining nations will not be tempted by the devil at the end of the thousand year reign of Christ upon this Earth (Revelation 20:1-9).
The martyrs beneath the alter are the victims of the Antichrist's initial rampage.
All evil will be eradicated sometime before the start of the new heavens and new earth as mentioned in Revelation. The actual Day of the Lord is the actual return, it happens at the end of the Tribulation:
He is clothed in a robe dipped blood, and the name by which he is called is The Word of God. And the armies of heaven, arrayed in fine linen, white and pure, were following him on white horses. From his mouth comes a sharp sword with which to strike down the nations, and he will rule" them with a rod of iron. He will tread the winepress of the fury of the wrath of God the Almighty. On his robe and on his thigh he has a name written, King of kings and Lord of lords. (Rev. 19:13-16)
That sword, the word used for sword there isn't the standard issue double edge sword all Roman soldiers had. It was double edge but like four feet long, it was used with great effect against advancing infantry. The enemies of Rome were terrified of it. It was called the
rhomphaia (
G4501 ῥομφαία)
Please take note the Bible mentions two different kinds of new heavens and new earths. They are not the same.
New Heavens & New Earth #1
(i.e. the Millennium)
The 1st "New Heavens and New Earth" mentioned in the Old Testament (Isaiah 65:17) and by Peter (2 Peter 3:13) is in reference to the Millennium. The Millennium takes place after Christ returns down from out of the clouds whereby He will destroy the remaining nations that will come up against Him. The Millennium also takes place after the Lord purifies this Earh by fire (which is similar to the global flood but it will leave no trace of this world behind; For not even a McDonald's sign will be accidentally found buried in the Earth. For the Earth's upper crust will be burned or turned into liquid hot magma).
New Heavens & New Earth #2
(Final New Heavens & New Earth)
The second "New Heavens & New Earth" as mentioned in Revelation 21:1 comes at the end of the Millennium and after the Judgment and eradication of evil. Satan, his minions, and wicked sinners will be no more. So when all evil comes to end forever, the final "New Heavens & New Earth" will arrive for God's people. This will be an entirely different and new planet whereby this planet will be no more.
I'm pretty much convinced that the new heavens and the new earth isn't the entire universe. It looks like the six day creation done a second time, this time it's permanent and perfect.
Also, back at the 7 year tribulation on this Earth (which is still yet a future event for us after the Pre-Trib Rapture): Well, these saints that were slain or killed for the Word of God and Jesus at the fifth seal are not in caves. They are dead souls crying out for vengeance over how they were murdered (Revelation 6:9-10). Yet, living saints are encouraged to forgive others and to pray and do good towards their enemies.
Do not take revenge, my dear friends, but leave room for God's wrath, for it is written: "It is mine to avenge; I will repay," says the Lord. (Rom. 12:19)
First century Christians did not take revenge, in fact, they believed that their persecutors we victims of a delusion. Those who slaughter this group are not given that consideration, they are children of perdition slaughtering out of a lust for bloody violence. God's response is interesting:
And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth? And white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellowservants also and their brethren, that should be killed as they were, should be fulfilled. (Rev. 6:10-11)
Fellow servants? I have always wonder who are the tribulation saints, it seems to me, they are those who reject the Antichrist and turn to God. They have their testimony, they witness to God's sovereign power just as the prophets and apostles did before them.
Anyways, here is a brief chronology of upcoming events:
#1.
Pre-Trib Rapture
#2.
7 Year Tribulation
(a) The Day of Lord begins at 6th seal.
(b) Christ's return (Armageddon)
(3rd part of the 6th vial)
#3.
Earth purified by fire (Conclusion of the Day the Lord)
#4.
The Millennium
#5.
The Judgment seat of Christ
#6.
The Great White Throne Judgment
#7.
Eradication of devil, demons, & wicked man
#8.
The Final New Heavens & New Earth
The way I organize the Revelation is seven seals, seven trumpets and seven vials of wrath. This approach divides them into three groups of seven chapters.
Seals
1) The Revelation of the Son of Man
2) 7 Letters to the 7 Churches
3) 7 Letters continued
4) 7 Lamps of fire (Menorah)
5) 7 Seals to be opened by the Lamb
6) 7 Seals opened, S-1 (seal one) thru S-5
7) The 144,000 sealed, the world hides from the Lamb
Trumpets
8) S-7 Silence, Trumpets sounded (T-1 thru T4)
9) T-5 Locusts, T-6 Euphrates
10) The Angel and the Little Book
11) The Two Witnesses clothed in sackcloth
12) The Woman, Child, Dragon
13) The Beast of the Land and the Beast of the Sea
14) 3 Angels proclaim: 144,000, Gospel, Wrath on 666
Vials of Wrath
15) 7 Angels given the 7 Vials of Wrath
16) Vials of Wrath: V-1 thru V-7
17) Babylon and the Beast with 7 heads
18) The wine of the wrath of her fall
19) The wedding feast of the Lamb
20) The Dragon bound 1,000 years
21) The New Jerusalem
Eternal State
22) The Healing of the Nations
The chronology is pretty easy to discern. The tribulation starts with the opening of the first seal so we know when that happens. The drama of the Two Witnesses unfolds about the middle, we know that because it says they witness for 3 1/2 years and the seventh trumpet sounds at the end of their witness. The vials come right at the end, they survive the vials and are gathering for the final battle they think they are going to win, it's over in an instant. Scene of the Beast rising out of a sea of humanity with Babylon sitting on it's back drinking the blood of the saints is between the last trumpet and the first vial, a space of 2 to 3 years. They spend that time having these big assemblies and hunting down anyone who will not take the mark.
As for the verse you are having trouble with: which verse may I ask is it? Maybe I can help.
And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever. (Rev. 20:10)
I have differed to the simplicity of the language, John's writings are the simplest in the New Testament. However the antecedent of day and night, forever and ever is clearly tormented.
Grace and peace,
Mark