At the judgment seat of Christ, believers are evaluated but never retried for salvation; sin cannot be raised as a charge, because the cross settled it. At the Great White Throne the dead are judged by their works, and the Book of Life shows who belongs to Christ. Your confidence rests in that book, not in a courtroom diagram.
The Grace Answer
These two scenes get blended together and terrify people who never needed to be afraid. Scripture presents them as distinguishable, though it does not spell out the event-structure with the precision some systems claim, and thoughtful Christians read them as two events or as one final judgment seen from different angles. Hold the framework humbly; hold the assurance firmly.
The judgment seat of Christ, sometimes called the bema, is where believers are evaluated. The word simply means a tribunal, the same term used for Pilate's judgment seat, so it is not by itself a rewards ceremony; that is an inference from what Paul says is examined there. And what is examined is your work, your building on the foundation, not a reopening of your case. Some work endures like gold; some burns like straw. Even when it burns, Paul is careful: the person himself will be saved. No one there loses salvation. Your forgiven sins are never dragged back out as charges that could condemn you, because the cross settled them once for all. Scripture can still bring hidden things to light, as the Lord will reveal the counsels of the hearts, yet Paul says the outcome for His own is that each one's praise will come from God. Disclosure, not re-condemnation.
A different throne
The Great White Throne, in Revelation 20, is the final judgment. The dead are judged according to their works, and the Book of Life is opened to show who belongs to Christ. The New Testament speaks of its end as a second death, a final loss, and that is held soberly and humbly rather than sensationalized.
Here is where your heart can rest. Your assurance does not hang on being absent from a particular courtroom image; it hangs on your name in the Book of Life. Whether believers are pictured as present or already vindicated, no one written there faces the second death. Your judgment already fell, on a Roman cross where Jesus stood in your place. There is now no condemnation for those in Him. And the verdict is not merely not guilty, as if you were returned to neutral. In Christ you have been made the righteousness of God. What remains for you is not a trial but a homecoming.