Physically dead but spiritually live. That what's going on right now. Those who have gone onto glory are spiritually in the presence of God, but await the final resurrection of their bodies. They are disembodied spirits in Hades, the place of the dead. (No, it's not on any map.) And then someday they will be like him.
Those of us believers on earth are spiritually alive but still face the possibility of physical death. "Death and Hades" have not yet been cast into the lake of fire.
Where in the scriptures are believers referred to as "the dead"?
"But concerning the resurrection of the dead, have you not read what was spoken to you by God, saying, ..." (Matt. 22:31)
"But even Moses showed in the burning bush passage that the dead are raised, when he called the Lord 'the God of Abraham, the God of Isaac, and the God of Jacob.'" (Luke 20:37)
"Then Jesus said to them plainly, 'Lazarus is dead.'" (John 11:14)
Who was Jesus talking about? Only unbelievers? Is that your theory?
You must discern between those spiritually dead (cf. Luke 9:60), and the physically dead.
"Who was Jesus talking about? Only unbelievers? Is that your theory?"
That is who John is talking about in Rev. 20. Believers have already been judged at Calvary and on physical death their works are judged. That's why Paul can say a crown of righteousness awaits him or to be absent from the body is to be present with the Lord. There is no holding one's breath to see if he gets a prize sometime in the future for the believer; he is in the presence where all is manifest before the One with whom we have to do.
When the Great White Throne judgment takes place the marriage supper has already taken place and the believers are already clothed. They have nothing to fear from Him who sits on the throne. They are not disembodied spirits for they are clothed. This judgment is for the unbelievers of all ages and it is a judgment for works that determines the severity of their eternal punishment (Matt. 11:21-22, "Woe unto thee, Chorazin! woe unto thee, Bethsaida! for if the mighty works, which were done in you, had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes. But I say unto you, It shall be more tolerable for Tyre and Sidon at the day of judgment, than for you").
"15 And anyone not found written in the Book of Life was cast into the lake of fire." Is just a statement where the eternal punishment is to take place. The unbelieving dead already know their names are not written in the Book of Life for where they are the presence of God is not.
If this is true who was it that Christ paraded before all to see when He descended and then ascended into the heavens?
1 Pet 4:6 6 For for this cause was the gospel preached also to them that are dead, that they might be judged according to men in the flesh, but live according to God in the spirit.
1 Pet 3:19 19 By which also he went and preached unto the spirits in prison;
Eph 4:8-10 8 Wherefore he saith, When he ascended up on high, he led captivity captive, and gave gifts unto men. 9 (Now that he ascended, what is it but that he also descended first into the lower parts of the earth? 10 He that descended is the same also that ascended up far above all heavens, that he might fill all things.)
Col 2:15 15 And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it.
These are several verses that state that Christ descended preached to captive, and then openly paraded them before the principalities His victory over them.
There is no such thing as soul sleep of the righteous. Absence from the body is to be in the presence with the Lord