[Regarding the timing of the Final Judgment detailed in the first paragraph of this post, I no longer agree with what I wrote. While this post accurately reflects the eschatology of the church I wrote it for (a member of the Foursquare Gospel Church of Canada), I would now-a-days more closely align myself with an Amilliannial view of the Millennium this is for many reasons, but some of the primary ones are the lack of biblical evidence for two returns of Christ (as in Dispensational Premellennialism) and the understanding that sin will continue beyond Christ’s second coming]
We believe that in the last day, following Christ’s millennial reign, there will be a final judgment of all believers, unbelievers, and angels. Jesus will be our Judge, and this judgment is what we call the “Great White Throne Judgment.” On this day those that have not believed in Jesus Christ will be punished for their rebellion against God, and those who believe will enter into blessing.
There will be a Judgment: It is made quite clear throughout the Scriptures that there will be a final judgment, where we will be judged for both the good and the bad that we have done (2 Cor. 5:10, Rom. 14:10, 12, Matt. 10:15; 11:22, 24; 12:36; 25:31-46; 1 Cor. 4:5; Heb. 6:2; 2 Peter 2:4; Jude 5, et al). In Revelation 20:11-15 we are told more about this judgment. We read that all, both great and small (v. 12), will be judged for their deeds, and all whose name does not appear in the book of life will be thrown into the lake of fire (v.15) (earlier we are told “This is the second death, the lake of fire” (v. 14)). Another picture we read of this final judgment is found in Matthew 25:31-46. Here we are told that all nations will be gathered before Jesus and will be judged, nations here is picturing a judgment of all individuals and not nations as a whole. We are told that He will separate the sheep (those who believe) from the goats (unbelievers), and the sheep will enter into the kingdom prepared by the Father for them from the foundations of the earth (v.32-34).
Unbelievers will be judged: This judgment will be of everyone who has ever lived, both believers and unbelievers (and angels, cf. Matt. 8:29; Jude 6). Unbelievers will be judged for their deeds (Rom. 2:5-7) and will receive judgment, in varying degrees, for their sins (Rev. 20:12, 13). In Luke 12:47-48 we read:
“47“And that slave who knew his master’s will and did not get ready or act in accord with his will, will receive many lashes, 48but the one who did not know it, and committed deeds worthy of a flogging, will receive but few. From everyone who has been given much, much will be required; and to whom they entrusted much, of him they will ask all the more.” (NASB)
In the surrounding passages Jesus is talking about being prepared for His second coming. It is in this context that we find this passage. We read that there will be different levels of punishment given out, but even those who are ignorant will still be punished (v. 48, cf. Rom. 1-3)(cf. Matt. 11:22; compare v. 24; Luke 20:47).
Believers will be judged: Writing to believers in Rome, Paul writes: “For we will all stand before the judgment seat of God… So then each one of us will give an account of himself to God” (Rom. 14:10b, 12) (cf. 2 Cor. 5:10; Rom. 2:6-11; Rev. 20:12, 15). Even though believers will be judged, we need not fear eternal condemnation for Jesus teaches: “24“Truly, truly, I say to you, he who hears My word, and believes Him who sent Me, has eternal life, and does not come into judgment, but has passed out of death into life” (John 5:24). Some believe that at this time we will have all our sins revealed, drawing this from 1 Cor. 4:5. But the context of this passage and the greater context of Scripture seem to go against this thought. In Micah 7:19 we read: “19He will again have compassion on us; He will tread our iniquities under foot. Yes, You will cast all their sins Into the depths of the sea.” And in Ps. 103:12; “12As far as the east is from the west, So far has He removed our transgressions from us” (cf. Isa. 43:25; Heb. 8:12, 17).
Christ will be our Judge: There are indications in Scripture that we will participate in the Judgment (Rev. 20:4; the twelve apostles will judge the twelve tribes of Israel Matt 19:28, cf. Luke 22:30), at the very least of angels (1 Cor. 6:3). But Jesus Christ is the one who will sit on the great white throne and He will be our Judge. In 2 Tim. 4:1 we read: “1I solemnly charge you in the presence of God and of Christ Jesus, who is to judge the living and the dead, and by His appearing and His kingdom” (Matt. 25:31-33; John 4:22, 27; Acts 10:42).
 Wayne Grudem, Systematic Theology : an Introduction to Biblical Doctrine (Leicester; Grand Rapids, MI: Inter-Varsity Press ; Zondervan, 1994), 1142.
 All scripture references are taken from the NASB
 Grudem, Systematic theology, 1144.