The following is completely the work of Kenneth Gentry. His response to the question is something I have faced multiple times and I appreciated his answers. It helps give some insight to the fitting of the loosing of Satan to the postmillennial framework as well as help explain some of the terminology from a preterist paradigm. Note, neither he nor I believe the millennial reign is over and Satan has already been loosed. But the interpretive work demonstrated here helps shed some light on how preterists attempt to consistently approach symbolical imagery in the book of Revelation.
Question from a reader:
"As I’ve been reading your whole series on Revelation, I have come to realize more and more how much we A-Mill Folks agree with you Post Mill Guys. But how does the loosing of Satan coincide with your postmillennial preterist hermeneutic? This seems to be the only area where I have a problem from the Preterist Viewpoint. Please advise where this fits."
This is a good question that touches on an issue that seems to confront both preterism (Satan’s loosing occurs after 1000 years in a book set to transpire shortly) and to undermine the idea of the universal conquest of the gospel expected by postmillennialism. Postmillennialism is a theological construct whereas preterism is a methodology, rather than a theology. Both merge well in my understanding of postmillennialism. Let me explain.
First, regarding the loosing of Satan after the 1000 year reign of Christ and how it impacts the preterist hermeneutic:
I would point out that although the vast majority of Revelation focuses on events that will occur "soon" (Rev 1:1, 3), Rev 20 presents us with a period of a 1000 years which appears to begin shortly (thereby fitting into the preterist expectation). But it is not necessary for it to be completed shortly, i.e., before AD 70. By necessity, 1000 years extends into the distant future. Otherwise, if we could compact 1000 years into a short time frame ("shortly come to pass," Rev 1:1), then why can we not just as legitimately declare that all the events that are to "shortly come to pass" speak of issues 1000 years or more years distant?
Yet is seems very clear that Revelation insists that its judgments are approaching in the very near future (Rev 1:1, 3; 6:9–11; 10:6c; 22:6, 10). This is a continuing drumbeat in Revelation. It must be speaking of the near term. That is, the main body of Revelation focuses on the near term.
But preterism is a hermeneutic insight, not a theological observation. Hermeneutically, Revelation’s main point comes to pass "soon" because "the time is at hand" (Rev 1:1, 3). Nevertheless, while its judgment prophecies are largely approaching, the preterist hermeneutic does not prohibit a glance at the long term implications of the near term events. That is, the great majority of judgments in Revelation will occur in the context of AD 70. But history does not end with AD 70; there are consequences to those judgment events. And those consequences look into the distant future.
Second, regarding the loosing of Satan after the 1000 year reign of Christ and how it impacts the postmillennial eschatology:
The very idea of a final rebellion of Satan fits easily into the postmillennial outlook. For in the first place, the idea of his loosing to initiate a rebellion indicates that until then he has not been able to exercise such an influence. It presupposes that he has been constrained, which is exactly what postmillennialism expects. (See earlier study on the binding of Satan.)
During the time of his binding, the gospel will go forth and gradually gain a greater and growing influence. Postmillennialists expect that the world will come under the dominant influence of the gospel which will remain a dominant influence for a long period of time.
Yet, according to God’s revelation in Scripture, the Lord will release Satan toward the very end so that he can gather out those who are merely "culturally Christian" but not truly regenerate. He will prompt these to revolt against the Christian majority in an attempt to disestablish the Christian faith. But as Revelation 20 shows, Christ’s return will crush him and the eternal state will begin in earnest.
The fact that he has an army as large as "the sand of the seashore" (Rev 20:8b) should not make us believe that this is the vast majority of the human race. This is a hyperbolic statement in an enormously symbolic book. And this figure is a common ancient image used of large-scale armies in (Jos 11:4; Jdg 7:12; 1Sa 13:5; 2Sa 17:11), various local populations (1Ki 4:20; Isa 10:22; 48:19; Jer 15:8; 33:22; Hos 1:10), the patriarchs’ offspring (Ge 22:17; 32:12), and so forth. In fact, the 1 Sam 13:5 reference specifically mentions only 30,000 chariots and 6,000 horsemen accompanying Philistia’s army. In 2 Sam 17:11 the writer is referring to early Israel’s own army, which could hardly approach this enormous number literally. In Jeremiah God speaks against Jerusalem warning that "their widows will be more numerous before Me / Than the sand of the seas" (Jer 15:8a). Sandy (2002: 41) notes that prophets often "express emotion rather than exactness . . . in order to shock listeners."
Thus, the loosing of Satan after a 1000 year period does not undermine either the preterist hermeneutic or the postmillennial theology.