Risen from the Dust
The idea of soul sleep is a common teaching in some Christian circles. Proponents of soul sleep generally do believe in the existence of human souls, but maintain that when a person dies their soul or consciousness remains in or connected to their flesh body. From there, they await the Resurrection of the Dead in a sleep-like state of suspended animation, thus the term "soul sleep".
While perhaps soul sleep is an improvement over some of the more traditional teachings about the afterlife, to say that the dead are in a state of deep sleep is not accurate. Soul sleep also works hand-in-hand with many false teachings. Most notably, it supports a physical resurrection scenario, where people's flesh bodies rise out of their graves (see ch.15 Resurrection of the Body). It is therefore worthwhile to understand why soul sleep isn't true, so as to avoid arriving at this, and other false conclusions.
One of the root teachings of soul sleep is that the dead are not cognizant or aware, but unconscious. However, when the afterlife is depicted in both the Old and New Testaments the dead are basically cognizant, not asleep. They are often described as having both thoughts and feelings that they can communicate.
For example, in the Old Testament it says, "The strong among the mighty shall speak to him out of the midst of hell [Sheol] with them that help him" (Ezekiel 31.21 KJV bible), "All they (the dead) shall speak and say unto thee, Art thou also become weak as we? art thou become like unto us?" (Isaiah 14.10 KJV bible), "let the wicked be ashamed, and let them be silent in the grave [Sheol]" (Psalm 31.17 KJV bible). In all of these examples, the dead are described as being awake and having thoughts and feelings they can communicate.
From the New Testament, we have the detailed account of the rich man and Lazarus, where a very poignant conversation takes place in Hades, "And he cried and said, Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue; for I am tormented in this flame. But Abraham said, Son, remember that thou in thy lifetime receivedst thy good things, and likewise Lazarus evil things: but now he is comforted, and thou art tormented" (Luke 16.24-25 KJV bible). Clearly this passage is not an allegory, but an account, that serves as a warning to individuals about the real consequences of not having compassion for others.
Another verse relating to soul sleep is in the book of Peter, where we learn that the gospel has already been preached (or proclaimed) to the dead, "For for this cause was the gospel preached [Greek: euaggelizo - to announce good news] 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" (1st Peter 4.6 KJV bible). On Judgment Day, the dead in Hades will be judged according to their deeds in the flesh. Therefore, while it is too late for them to be firstfruits unto Christ, they do have the comfort of knowing that Jesus defeated death, and will raise them up in the second resurrection of the dead. It would not have been possible for the dead to hear this good news, unless they were somewhat conscious.
If the dead are asleep and unconscious, it would not be possible (before the resurrection) for Moses and Elijah to appear on the Mt. of Transfiguration, "And, behold, there appeared unto them Moses and Elias talking with him" (Matthew 17.2-3 KJV bible). Also, relating to soul sleep, we have the witness of the book of Revelation. In ch. 7, a great multitude of believers (from the tribulation) gather and praise the Lord in Paradise, "After this I beheld, and lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands; And cried with a loud voice, saying, Salvation to our God which sitteth upon the throne, and unto the Lamb" (Revelation 7.9-10 KJV bible). From this passage alone, we know that the souls of the righteous are both awake, and with the Lord in heaven (see also ch.4 Souls in Heaven). Lastly, one should consider what Jesus says in John 8.56, "Your father Abraham rejoiced to see my day: and he saw it, and was glad" (John 8.56 KJV bible). If Abraham is in a state of soul sleep, then how could he have rejoiced at the day when Messiah was born into the world?
There are many variations of soul sleep. One widespread principle of soul sleep is that when a person dies, their soul remains in or connected to their flesh body. However, it is well established in scripture, that when a person dies their soul does not remain within their flesh body. Rather, the soul moves on, and the body is left as an empty vessel.
When God answers Elijah's prayer by resurrecting the widow's son, it is written that the child's soul returns to him. This indicates that initially when the boy dies, his soul leaves him, "And he stretched himself upon the child three times, and cried unto the LORD, and said, O LORD my God, I pray thee, let this child's soul [nephesh] come into him again. And the LORD heard the voice of Elijah; and the soul of the child came into him again, and he revived" (1st Kings 17.21-22 KJV bible). Also, when Rachel dies giving birth to Benjamin it's written that her soul departs from her, "And it came to pass, as her soul [nephesh] was in departing, (for she died) that she called his name Ben-oni" (Genesis 35.18 KJV bible). Job describes how at the end of his earthly struggle the Lord will long for the work of his hands, meaning Job's soul, "If a man die, shall he live again? all the days of my appointed time [Hebrew: tsebawaw - campaign or service] will I wait, till my change come. Thou shalt call, and I will answer thee: thou wilt have a desire to the work of thine hands" (Job 14.14-15 KJV bible). Clearly, the soul leaves behind the flesh body at death, which is inconsistent with many versions of soul sleep.
In the New Testament, when Stephen is about to become a martyr, is he in error to call upon Jesus to receive his spirit, "[Stephen] looked up stedfastly into heaven, and saw the glory of God, and Jesus standing on the right hand of God...And they stoned Stephen, [who was] calling upon God, and saying, Lord Jesus, receive my spirit [pneuma]" (Acts 7.55,59 KJV bible)? Also, the book of Acts describes how during one of Paul's sermons a young man falls down from a third story window. Then Paul says, "Trouble not yourselves; for his life [psuche] is in him" (Acts 20.10 KJV bible). This indicates that if the young man had died, his soul or person (psuche) would have left his body, which it apparently did not.
If the soul stays within the body, then why does Jesus tell the malefactor on the cross that that very day he would be with him in Paradise, "And Jesus said unto him, Verily I say unto thee, Today shalt thou be with me in paradise" (Luke 23.43 KJV bible)? Also, Peter speaks of "putting off" his earthly tent or dwelling after his time in the flesh, "Yea, I think it meet, as long as I am in this tabernacle, to stir you up by putting you in remembrance; Knowing that shortly I must put off this my tabernacle, even as our Lord Jesus Christ hath shewed me" (2nd Peter 1.14 KJV bible). While there are many variations of soul sleep, clearly the widespread idea that the soul or consciousness remains within the body after death, has no scriptural support.