From https://reasonsforhopejesus.com/soul-sleep/:
The doctrine of soul sleep claims that the soul literally sleeps until the time of the bodily resurrection when it is awakened. During this time the person is not conscious and has no awareness of their condition or state. This teaching also claims that the soul resides in the memory of God until its awakening. Seventh Day Adventists teach this doctrine, but it is a completely false teaching with absolutely no biblical support. And, there is a great deal of biblical information to prove it false.
Jehovahs Witnesses teach a variation of this doctrine called annihilation, which claims the body and soul cease to exist at death. This teaching is similar to the Seventh Day Adventists teaching of soul sleep, but different in that the soul lies in a state of death (not unconscious sleep) until it is made alive (not awakened) in the bodily resurrection. (Read about the death of a celebrity Jehovahs Witness and information about how to witness to Jehovahs Witnesses.)
Soul Sleep A False Teaching
Both of these teachings are in grave error (pun intended). Although both the Seventh Day Adventists and the Jehovahs Witnesses use Scripture to support their beliefs, they do so incorrectly. The apostle Peter spoke of such teachings coming from people who are unlearned and unstable and therefore they twist the Scripture (2 Peter 3:16) and make it say something that it does not teach. So, what Scripture do they twist and misinterpret?
Both Seventh Day Adventists and the Jehovahs Witnesses use a verse from Ecclesiastes as the foundation for their doctrines. They take this verse out of context to support what they believe:
Ecclesiastes 9:5 needs to be understood in the full context. These are The words of the Preacher, the son of David, king in Jerusalem (Ecclesiastes 1:1) and he is speaking from a human, or earthly, perspective about physical death. He is not making doctrinal statements about the condition of the soul after death. The soul is not physical, it is spiritual. The Preacher is not saying that the soul dies, nor is he saying that it enters into an unconscious state at death. He is speaking of a persons earthly existence ceasing, the futility of earthly gain and the fleeting influence of the departed.
Our Souls After Death
So what does the Bible say about the eternal destiny of our souls? In the New Testament we find clear teachings about what happens to the soul at death. Paul, with full knowledge and understanding of redemption of sin by Christs death on the cross and eternal life made possible by His resurrection, speaks of our physical death and the resurrection of the soul:
Paul is certain that, when he dies, he will go and be with the Lord. He does not say, to be absent from the body, and to [someday in the future] be present with the Lord. He proclaims that the soul leaves the body and enters into the presence of the Lord immediately at death. Paul also says,
Pauls Desire
If Paul had thought his soul would only be sleeping for the period of time from death to bodily resurrection, he would not have desired to die. His desire to die was based on a desire to go and be with Jesus. Based on his commitment to preaching the gospel, and his desire to have people come to know Jesus, Paul would have preferred to live and serve Christ than to have slept in the grave until Jesus return.
Paul spoke of his desire to depart, and to be with Christ right after he said, For to me to live is Christ, and to die is gain. (Philippians 1:21) When Paul said to live is Christ he was speaking of his purpose and meaning in life that came from knowing and serving Jesus. Therefore, to die would not have been gain if his soul were to sleep. But Paul said it is gain (verse 21), because he knew that at death he would go to be with Christ (verse 23) in Heaven.
Theres another precious teaching in this verse that cannot be passed by. Although it is not relative to our discussion of soul sleep, we must pause and make note of it.
Paul knew that while he remained here on earth, Christ was here with him. He said, to live is Christ. Christ is here on earth with every believer, through the power and presence of the Holy Spirit.
The Death of the Body
Its important that we clearly understand what happens at death, not only to refute false teachings such as soul sleep and annihilation but also so we live with confidence of the joy we will enter into when we take our last breath and depart this world. We know from Genesis that Adam was created from the dust of the ground and both Genesis and Ecclesiastes tell that our bodies will return to the earth:
Destiny of the Spirit for Man and Animal
Ecclesiastes 12:7 clearly tells that the spirit of man returns to God who gave it and Hebrews 9:27 tells us, it is appointed unto men once to die, but after this the judgment. Whether it is an unregenerate spirit or a spirit made alive by the Holy Spirit, God will judge both at the time of death. Ecclesiastes 3:21 confirms this, Who knows the spirit of man that goes upward, and the spirit of the beast that goes downward to the earth?
The spirit of a beast (animal) goes into the ground, but mans spirit goes to God (Ecclesiastes 3:21) for judgment (Hebrews 9:27). Remember that man is an eternal being and all souls will live eternally after the bodily death. The question is not whether man will spend eternity somewhere, but rather where man will spend eternity.
Jesus Teaching Denies Soul Sleep
Jesus account of Lazarus and the rich man in Luke 16 further refutes the possibility of any truth in the doctrine of soul sleep. Both Lazarus and the rich man are bodily dead, but both men are fully aware of their condition and their location.
Both of these men had experienced physical death and their bodies had gone into the earth to return to dust. Yet the souls of both men lived on.
More Reasons to Deny Soul Sleep
There are many more verses that support our souls going to be with the Lord at the time of our physical death. We know that the body dies, so Jesus words of promise in these verses are regarding the soul:
Its also clear in these verses from Revelation that souls do not sleep. Revelation 6:9-10 speaks of the martyrs in the end times and tells that their living souls are in Heaven and they are conscious.
Still another verse that confirms there is no soul sleep is Psalm 116:15. Why would the death of Gods saints be precious in His sight if souls slept in the grave? The soul lives on. And for Christians, we enter into the Lords presence at death.
Finally, perhaps one of the best verses for the proof of conscious life of the soul following death is found in Luke 23:43, And Jesus said to him, Assuredly, I say to you, today you will be with Me in Paradise.
So; after all of that; just who are going to be judged at the GWT judgment?