Translation
Blessed and holy is anyone who takes part in the
first resurrection; the second death has no power over them, rather they will be
priests of GOD and of CHRIST and will
reign with Him for one thousand years.
Paraphrase
Blessed and holy is anyone who takes part in the first resurrection; the second
death has no power over them,
rather they will be representatives on earth of THE CREATOR AND OWNER OF ALL THINGS and of THE SPIRIT-ANOINTED SAVIOR, and will be instruments of His authority in a complete, unstoppable and lasting way.
The Significance of a 1000 Year Reign
1000 means “fullness or completeness.” Since 1,000 is a multiple of 10 it represents the power to make one’s rule into a lasting dynasty. Most earthly dynasties last only about 200 years, so a dynasty of 1,000 years would demonstrate true and lasting authority. The fact that Satan is bound for 1000 years shows that he does not have that kind of power while someone else does (and we know who that is).
Is 1,000 years symbolism or a literal 1,000 years? Everything else in Revelation seems to make more sense as symbolism, so it is likely that this is also symbolism.
This is a picture of true dominion. A dynasty of 1,000 years is a dynasty with true authority; it is unstoppable.
Why Satan must be released is not explained, therefore we cannot know, and therefore speculation about it is futile. In the mind of God it makes perfect sense and is even necessary.