20:7And when the thousand years are completed, Satan will be released from his prison,

And when the THOUSAND YEARS are COMPLETED,

This is precise time; it is exactly 1,000 years. Just as the rest of the Revelation gives precise times, for example Revelation 12:6, so too, this millennial period is precise. Different phrases such as a "short time" (Revelation 12:12) are used to denote imprecision (or perhaps, to keep the Devil guessing).

There can be no doubt that this millennial period will be COMPLETED. Time is the only dimension which always goes forward, and thus COMPLETED. It is not like the linear dimensions which may be "to" or "from" some point. Linear dimensions also lead to some interesting physical places, such as the bottomless pit (Revelation 9:1-12). It apparently has side to side dimensions and a top, but there is no end to the bottom.

SATAN will be released from his PRISON,

Now this seems odd. The beast and the false prophet are permanently gone from this earth Revelation 19:20), but Satan has only been bound in PRISON (verse 2). Scholars have given many reasons why this is so. It could be that Jesus Christ wants to give SATAN one more chance to repent and acknowledge Jesus Christ as Lord and Savior (2 Peter 3:8-9-13). It has been suggested that those alive coming into the millennial period still contain the sin curse within their nature. It is a genetic part of all humans since the fall (Genesis 3:22-24).

Since the millennial period is a Theocracy by a RIGHTEOUS KING, Jesus Christ. open sin is unheard of. If a sin is brought out into the open, the sinner is dealt with swiftly by death (Isaiah 65:17-20-25 and Ezekiel 32:17-21). So at the end of the 1,000 years, the then population of the earth is well conditioned to not commit any sin(s). But the sinful nature of man lurks just below the surface, and the release of SATAN will test the human's CHOICE one more time (next verse).

Lastly, when the 1,000 years are COMPLETED, the earth's inhabitants probably don't have any recollection of what happened 1,000 years earlier. Dim memory of an uptaking, dim memory of a horrible seven year tribulation, and dim memory of SATAN's incarceration. To prove my point. which of us recall what happened one thousand years ago. My point is made.