In his article “Har Magedon: The End of the Millennium,”  Meredith G. Kline reviewed a previous study by C. C. Torrey on the Hebrew term translated as har magedōn, and showed how this is significant for the millennium debate. Kline identified this as a reference to Mount Zaphon or Mount Zion, and said it is parallel or equivalent to har mo‘ēd in Isaiah 14:3, the “Mount of Assembly.” He wrote: 
This in turn proves to be of critical significance in the millennium debate. For it adds a final, decisive point to the traditional amillennial argument for the identification of the conflict marking the end of the millennium (Rev 20:7–10) with the climactic battle of the great day of the Lord to which the Apocalypse repeatedly returns, as in the Rev 16:12–16 account of the Har Magedon encounter itself and the Rev 19:11–21 prophecy of the war waged by the messianic judge.
Kline identified the battle mentioned in Revelation 16:12-16 with the gathering of the hordes of Gog and Magog in 20:8-9, the invasion described in Ezekiel 38-39. He wrote: 
The war (polemos) of Rev 20:8 is certainly “the war of the great day of God, the Almighty,” the battle of Har Magedon described in 16:14-16. In each case it is the war to which Satan, the dragon, gathers the nations of the whole world. This universal gathering against the Lamb and the city beloved of the Lord is also referred to as Satan’s deception of the whole world through the signs wrought by his agents, the beast from the sea and, particularly, the false prophet. Indeed, this theme of the deception-gathering appears in a series of five passages in the Apocalypse, concentrically arranged according to the subject(s) of the action, with 16:13-16 the centerpiece and 20:7-9 the concluding member. Satan as the ultimate deceiver is the subject in the first member of the chiasm (12:9) and in the last (20:7-9), where the deception is specified as the gathering. The false prophet, acting in association with the dragon-like beast, is the subject in the second member (13:14), which speaks of his world-deceiving signs, and in the fourth (19:17-20), where his deceptive signs are identified with the gathering of the kings of the earth against the messianic horseman and his armies. At the center of the chiasm (16:13-16) all three subjects appear together as the source of the demonic signs by which the kings of the whole earth are gathered to Har Magedon for the great war. This identification of Satan with his two agents in the disastrous enterprise is also brought out in the fifth member of the chiasm (20:10).
In Revelation 16:14 the gathering of the people of the world at Armageddon is described, but there is no description there of an actual battle, or the outcome, but the account in Revelation 20:8-9 includes both the gathering of the nations, and the judgment that falls on them.
Kline supported amillennialism, and in a previous article, he argued that the first resurrection in Revelation 20:4, and the thousand year reign of the saints is a post-mortem affair. He wrote: 
The proper decipherment of “the first resurrection” in the interlocking schema of first-(second) resurrection and (first)-second death is now obvious enough. Just as the resurrection of the unjust is paradoxically identified as “the second death” so the death of the Christian is paradoxically identified as “the first resurrection.” John sees the Christian dead (v. 4). The real meaning of their passage from earthly life is to be found in the state to which it leads them. And John sees the Christian dead living and reigning with Christ (vv. 4, 6); unveiled before the seer is the royal-priestly life on the heavenly side of the Christian’s earthly death. Hence the use of the paradoxical metaphor of “the first resurrection” (vv. 5f.) for the death of the faithful believer. What for others is the first death is for the Christian a veritable resurrection!
Kline rejected the alternative amillennial interpretation, which says that the first resurrection is not the literal death of a Christian but their spiritual regeneration, and that “beheading” in Revelation 20:4 is a metaphor representing their submission to God as Lord and King. He wrote: 
The other major amillennial interpretation of “the first resurrection,” which views it as regeneration or baptism into Christ, would also meet the contextual requirement that protos refer to an experience within the present course of history. However, it does not handle satisfactorily the paradoxical schema we have been examining; in particular, it misses the clear correlation of first death and “first resurrection” in this pattern. It also encounters other difficulties. If “the first resurrection” were regeneration, the death of which “the first resurrection” was the triumphant reversal would be fallen man’s death in sin, his unregenerate state. But the living and reigning (v. 4) which is “the first resurrection” (v. 5) is surely to be regarded as answering to the death experience described earlier in the same verse, the death of Christian martyrdom: “( I saw) the souls of them that were beheaded for the witness of Jesus . . . and they lived.” Though this martyrdom imagery is apparently a concrete, typical individualization of a more general kind of experience and is in that sense figurative, it is clearly a Christian experience that this figure portrays. Martyr death would obviously be a most unsuitable figure to depict death in sin. It would be incongruous even for the Christian experience of dying to sin. Those who participate in “the first resurrection” are not those who are dead in sins but those who are righteous in Christ. Their martyrdom is not the kind of death for which spiritual regeneration would be the remedy, but it is itself a consequence and seal of a spiritual regeneration that has been manifested in faithful Christian witness (cf. Rev. 2:10; 12:11). The same problem surfaces in the reference to “the rest of the dead” who do not take part in “the first resurrection” (v. 5). On the interpretation under criticism this would be another group of the unregenerate and verse 5 would then become a rather pointless statement to the effect that the unregenerate are unregenerate during the thousand years. However significant the theological observation that triumphant Christian death belongs to a spiritual process whose source is regeneration, spiritual resurrection from death in sin simply is not what is meant by “the first resurrection” in Revelation 20:5f.
Unfortunately, Kline seems to have completely missed the real meaning of the metaphor of “beheaded” in Revelation 20:4. It is not referring to martyrs.
The beheading mentioned in Revelation 20:3 affects four things: the mind, or thoughts; the eyes; the ears; and the tongue.
On the first of the four, the mind or our thoughts, Paul said: “For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds; Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ.” [2 Corinthians 10:4-5] Beheading in Revelation 20:4 encompasses this idea of bringing our thoughts into captivity.
On the second, Jesus said, “And if thy right eye offend thee, pluck it out, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into Gehenna.” [Matthew 5:29] Jesus also said, “The light of the body is the eye: therefore when thine eye is single, thy whole body also is full of light; but when thine eye is evil, thy body also is full of darkness.” [Luke 11:34] He refers to the eye in a spiritual sense; on several occasions he referred to the Pharisees as “blind.” The idea of beheading in Revelation 20:4 includes the teaching of Jesus on the eye, and man’s need for spiritual enlightenment from Christ, who is “the true Light, which lighteth every man that cometh into the world.” [John 1:9]
Jesus said his disciples were blessed, because they were privileged to hear his words and understand them. [Matthew 13:14-17]
Hebrews 5:9-13 says, referring to Christ: “And being made perfect, he became the author of eternal salvation unto all them that obey him; … Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing. For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat. For every one that useth milk is unskilful in the word of righteousness: for he is a babe.” All this relates to hearing in the spiritual sense.
On the tongue, much is said in the New Testament. Jesus said, “Do not ye yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught? But those things which proceed out of the mouth come forth from the heart; and they defile the man. For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies: These are the things which defile a man: but to eat with unwashen hands defileth not a man. [Matthew 15:17-20]
James wrote on the tongue: “My brethren, be not many masters, knowing that we shall receive the greater condemnation. For in many things we offend all. If any man offend not in word, the same is a perfect man, and able also to bridle the whole body. Behold, we put bits in the horses’ mouths, that they may obey us; and we turn about their whole body. Behold also the ships, which though they be so great, and are driven of fierce winds, yet are they turned about with a very small helm, whithersoever the governor listeth. Even so the tongue is a little member, and boasteth great things. Behold, how great a matter a little fire kindleth! And the tongue is a fire, a world of iniquity: so is the tongue among our members, that it defileth the whole body, and setteth on fire the course of nature; and it is set on fire of Gehenna. For every kind of beasts, and of birds, and of serpents, and of things in the sea, is tamed, and hath been tamed of mankind: But the tongue can no man tame; it is an unruly evil, full of deadly poison. Therewith bless we God, even the Father; and therewith curse we men, which are made after the similitude of God. Out of the same mouth proceedeth blessing and cursing. My brethren, these things ought not so to be. [James 3:1-10]
The thoughts, the eyes, the ears and the tongue are all involved in the spiritual beheading that John refers to in Revelation 20:4. It is those who fulfill these things who reign with Christ; this is now, in their present lives. Reigning with Christ is promised to believers in this age. The saints of God have been given the Spirit of Christ, who is King and Lord of all. And so, having in them the Spirit of the King, those who have been figuratively beheaded, and who do not worship the beast, are called kings, and reign as kings and priests with him in this present life. This is not properly amillennialism, but I prefer to call it discrete millennialism.
Returning to the article on Armageddon, Kline wrote: 
The relationship of Rev 20:7-10 to Ezekiel 38-39, obvious enough from the adoption of the Gog-Magog terminology in Revelation 20, is also evidenced by a set of basic similarities: the marshaling of hordes from the four quarters of the earth (Ezek 38:2-7, 15; 39:4; Rev 20:8); the march of the gathered armies to encompass the saints in the city of God, center of the world (Ezek 38:7-9, 12, 16; Rev 20:9); the orchestration of the event by God (Ezek 38:4, 16; 39:2, 19; Rev 20:3, 7); the timing of the event after a lengthy period in which God’s people were kept secure from such a universal assault (Ezek 38:8, 11; Rev 20:3); the eschatological finality of the crisis (Ezek 39:22, 26, 29; Rev 20:10 ff.); and the fiery destruction of the evil forces (Ezek 38:22; 39:6; Rev 20:9-10).
Just as clearly, the Gog-Magog prophecy of Ezekiel 38-39 is a primary source drawn on by Rev 16:14-16; 19:17-21 and the other Apocalyptic prophecies of the final conflict. Prominent in these passages is the major feature that marked the dependence of Rev 20:7-10 on the Ezekiel prophecy– namely, the universal gathering of the enemy armies (Rev 16:14-16; 17:12- 14; 19:19; and compare 6:15 with Ezek 39:18-20), including too the historical setting of that event at the close of this world-age (Rev 6:12-17; 11:7-13; 16:16-17 [cf. 17:10-14]; 19:15-21), following an era in which it is given to the Church to fulfill its mission of gospel witness (11:3-7; cf. 12:6, 14).
Further (and of central interest in this essay), the Har Magedon of Rev 16:16 is identifiable with Mount Zaphon, the provenance of Gog in Ezekiel 38-39. Particularly important is the significance of this location for the identity of Gog. His claimed lordship over the Zaphon site of the divine council, a challenge to the true Lord of Har Magedon, reveals the Gog of Ezekiel 38- 39 to be the bestial antichrist agent of Satan in the Apocalyptic prophecies of the war of the great day. Such self-exaltation over all that is called God is the affront of this man of sin that provokes the parousia of the Lord Jesus to overthrow and destroy him (2 Thess 2:3-10). The pseudo-parousia attributed to this antichrist, a spectacle of satanic deception (2 Thess 2:9), is another feature found in Ezekiel’s prophecy where, as we have noted, Gog’s coming is portrayed as an advent in storm-cloud theophany (Ezek 38:9, 16). Also, beast symbolism is used for the antichrist phenomenon in Revelation, and beast imagery is applied to Gog in Ezek 38:4; 39:2. Extensive evidence of the Ezekiel source is afforded by the Apocalyptic accounts of God’s judgment on the beast. Instruments of judgment mentioned by both Ezekiel and John include earthquake (Ezek 38:19-20; Rev 6:12; 11:13; 16:18-20), sword (Ezek 38:21; Rev 19:15, 21) and destructive hail and fiery brimstone (Ezek 38:22; 39:6; Rev 16:21; 19:20). Most striking is the distinctive motif of God’s summoning the birds and beasts to feed on the carcasses of the defeated armies Gog had gathered, the banquet theme elaborated in Ezek 39:4, 17-20 and incorporated into the account of Christ’s victory over the beast and his assembled armies in Rev 19:17-18.
The conclusion is amply warranted that Ezekiel 38-39 is the common source of Rev 20:7-10 and the passages earlier in Revelation that deal with the eschatological battle. This confirms the standard amillennial contention that the Gog-Magog episode of Rev 20:7-10 is a recapitulation of the accounts of the Har Magedon crisis in these other passages. And the capstone for that argument is what we have discovered about the equation of Har Magedon (mo‘ēd) with Gog’s place, Magog, the equation established by the Zaphon connection in Isa 14:13; Psalm 48; Ezekiel 38-39. It now appears that the very term har magedon itself identifies the Rev 16:14-16 event as the Gog-Magog event of 20:7-10.
Revelation 20:7-10 is not, as premillennialists would have it, an isolated, novel episode, not mentioned elsewhere in the book of Revelation. Rather, it belongs to a series of passages, including Rev 19:11-21, which premillennialists rightly regard as referring to the antichrist-Har Magedon crisis and the parousia of Christ. It therefore follows that the thousand years that precede the Gog-Magog crisis of Rev 20:7-10 precede the Har Magedon-parousia event related in the other passages. Har Magedon is not a prelude to the millennium, but a postlude. Har Magedon marks the end of the millennium. And that conclusion spells the end of premillennialism.
The conclusion that Har Magedon is the end of the millennium also contradicts the preterist approach to the Apocalypse. Preterists interpret the series of passages (except for Rev 20:7-10) that we have taken as prophecies of the final conflict as referring instead to past events, like the fall of Jerusalem or the collapse of the Roman empire. This approach with its drastic reductions of the Apocalyptic emphasis on the final global Gog crisis is understandably popular with postmillennialists, whose distinguishing notion is that the present age, the millennium, is–at least in its latter phase–a time not only of surpassing evangelistic success for the Church but one of outward prosperity and peace. Indeed, postmillennialism of the theonomic reconstructionism variety, in keeping with the theonomic insistence that Torah legislation enforcing the theocratic order is definitive of the Church’s duty today, anticipates that the millennial success of the Church’s mission will involve its worldwide political dominance and the forcible elimination of public practice of non-Christian religions. They expect a fulfillment in this Church age of the OT prophecies of the restoration of the kingdom in the dimension of external dominion to the ends of the earth.
For such postmillennial expectations, the Biblical forecast of a global surge of anti-Christian forces as the immediate precursor of the parousia is obviously a problem. The postmillennialists’ strategy is to confine the problem to Rev 20:7-10 by adopting the preterist approach and then to try to minimize the enormity of the crisis described in that passage. But once the preterist option is removed, their exegesis loses all plausibility as they attempt to deal with the whole series of Har Magedon-Gog passages and the recurring, progressively elaborated theme of the worldwide suppression of the gospel witness in which the millennium issues. Actually, Rev 20:7-10 by itself refutes the postmillennial projections, for it is evident there that the nations of the world have not become officially “Christianized” institutions during the millennium. That is in accord with the consistent eschatological pattern of Scripture. In the visions of Daniel 2 and 7, for example, the imperial power clearly retains its beast-character throughout history, ultimately prevailing against the saints. Not until the parousia of the Son of Man and the final, total elimination of the bestial empire do the people of the Most High receive the kingdom of glory and universal dominion.
Recognition of the identity of the Har Magedon and Gog-Magog events thus proves to be decisive for the rejection of any view, premillennialist or postmillennialist, that understands the millennium as an age that witnesses the fulfillment (at least in a provisional form) of the OT prophecies of the coming of God’s kingdom in external earthly grandeur. The kingdom of glory does not come until final judgment is executed against antichrist/Gog, and therefore not before the end of the millennium. There is no transitional stage in its appearing between the first and second advents of Christ. The glory kingdom comes only as a consummation reality and as such it abides uninterrupted, unchallenged for ever and ever.
Here is the fundamental difference in the eschatology of the several millennial views, the difference that our names for them should reflect. Two of the views are pre-consummation. They hold that a (transitional) realization of the OT prophecies of the kingdom as an external imperial power occurs during the millennium and thus before the consummation. These two can be distinguished from each other in terms of how they relate the millennium to the parousia as pre-parousia (the postmillennialists) and post-parousia (the premillennialists). The amillennial position alone represents the postconsummation view of the coming of the kingdom of glory.
The identity of the battle referred to in Revelation 16:14 and the events in 20:8-9 also supports discrete millennialism, the reign of the saints who are figuratively beheaded together with Christ, in their present lives.
1. Meredith G. Kline. “Har Magedon: The End of the Millennium” JETS 39 (June 1996): 207-222
4. Meredith G. Kline. “The First Resurrection” WTJ 37 (1974/75): 366-375.