'Completed' in the Bible

but when it is time for the trumpet call of the seventh angel, when he is about to sound, then the mystery of God [that is, His hidden purpose and plan] is finished, as He announced the gospel to His servants the prophets.

The rest of the dead [the non-believers] did not come to life again until the thousand years were completed. This is the first resurrection.

And when the thousand years are completed, Satan will be released from his prison (the abyss),