Few facts to consider: note that they who overcame the beast, with everything that has to do with it are said to live and "reign with Christ a thousand years".The question is: what starts at the beginning of the thousand years? read the following verse: "Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years."--verse 6. Additional fact is given that for this thousand year period that they who took part in the first resurrection shall also "reign with Christ a thousand years". Then we can safely see that the thousand year period starts at the first resurrection. Now this brings us to another question; when will the first resurrection takes place? the answer for this will enable us know for a certain what "marks" the thousand years spoken of.
Christ said there are primarily two separate types of resurrections which will happen in the future, for this he said: "...for the hour is coming, in the which all that are in the graves shall hear his voice, and shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation." --John 5:28, 29..Daniel also in support in holy vision saying: "And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt."--Daniel 12:2. Thus from Revelation 20: 6 when it says " Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power.." refers to those who are resurrected to everlasting life, that which Christ and Daniel testify. And this resurrection takes place at the second coming of Jesus: "For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first..."--1 Thessalonians 4:16-- HENCE the second coming of Christ marks the beginning of the thousand year period.
After discovering this, where then will Jesus and the saved spend this period? Christ speaking of his coming says: "Let not your heart be troubled: ye believe in God, believe also in me. In my Father's house are many mansions: if it were not so, I would have told you. I go to prepare a place for you. And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also."--John 14:1-3. Here we see Christ's promise to his followers that his return to earth is to take them to Heaven, and having seen that the first resurrection, which is the resurrection of life, takes place at the second coming, we are to understand that the saved will spend the millennium in Heaven and not earth! This also we see of the fact that Jesus will not even touch the earth when he comes but will be met in the air, taking the saved home to heaven for a thousand years:"Then we which are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air: and so shall we ever be with the Lord."--1 Thessalonians 4: 17.
Since the saved will be in heaven for the period of the thousand years, where will the wicked be?---"...and they [the saved]lived and reigned with Christ a thousand years... But the rest of the dead lived not again until the thousand years were finished."--So the resurrection here of the wicked happen after the thousand years--while during the thousand year period when the saved are with Christ in heaven, the wicked did not live but were dead. Then what will become of this earth?---"I beheld the earth, and, lo, it was without form, and void; and the heavens, and they had no light...I beheld, and, lo, there was no man, and all the birds of the heavens were fled...I beheld, and, lo, the fruitful place was a wilderness, and all the cities thereof were broken down at the presence of the LORD, and by his fierce anger."--Jeremiah 4:23,25,26...A clear terrible description of the earth during the millennium which begins at the second coming-that there will be no humans during the period on earth-- the saved being taken to heaven for the millennium, and the wicked all dead until the period end.
So what is this popular belief of an earthy millennium where Christ reigns in it? with peace? When it has no foundation in the Bible? I can leave you with only a verse to ponder on: "For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape."--1 Thessalonians 5:3