Blessed and holy is the one who shares in the first resurrection! Over such the second death has no power, but they will be priests of God and of Christ, and they will reign with him for a thousand years.
Six times in the first seven verses of Revelation 20 the phrase “thousand years” is mentioned. I firmly believe this means something, and there is no reason not to see it as a literal time span. But in all fairness, there are competing interpretive views that are within the pail of evangelical orthodoxy. The ESV study Bible provides a succinct summary:
“These verses are among the most controversial in Revelation. Responsible scholars disagree regarding the meaning of the “thousand years” in vv. 2–7 (see Introduction: Millennial Views). The three main views are represented by: (1) Premillennialists (those who believe Christ will return “pre” [before] the millennium) think that this thousand years (Latin, millennium) is a future time of great peace and justice, which is usually thought to be a literal 1,000-year period that will begin when Christ returns to reign on earth as a physically present King, and which will include resurrected believers reigning with him. (2) Postmillennialists (those who believe that Christ will return “post” [after] the millennial period) think that before Christ returns to earth the gospel will spread and triumph so powerfully that societies will be transformed and peace and justice will reign on earth for a thousand years (or for a long period of time), after which Christ will return for the final judgment. (3) Amillennialists (those who hold an “a” [non-literal] millennial view) think this thousand years is the same period as this present church age, and that there will be no future “millennium” before Christ returns for the final judgment. Related to this is the question of whether the thousand years are to be interpreted literally (most premillennialists hold this view) or symbolically (most postmillennialists and amillennialists and some premillennialists hold this view). Those holding each view read John's millennial vision in terms of their understanding of other biblical texts and their approach to prophetic literature as a whole. Likewise, each of these views falls within the framework of historic Christian orthodoxy.”
It would seem to me that both amillennial and poststmillennial viewpoints must as a rule at some point interrupt a literal, plain interpretation of scripture in order to arrive at their destinations theologically. In my opinion, premillennialism maintains the most consistent hermeneutic. It is not without its questions and rough spots, but it is most consistent with plain interpretation. I also believe it has the benefit of being the easiest view to integrate Old Testament prophecy into the picture of the Book of Revelation. At times, it is virtually seamless, particularly with the Book of Daniel in the Old Testament. These two facts (hermeneutic and biblical prophetic harmony) are why I am still a committed premillennialist. My committed reformed friends have yet to provide convincing theology to the contrary.