Note: All Scripture quotations found in this article are from the text of the Authorized King James Version of the Bible.
Soul Sleep is a heresy taught by cults such as the Mormons, Seventh-Day Adventists and Jehovah Witnesses. It is the false doctrine that teaches that the soul of a dead person is unconscious until the Second Coming of the Lord Jesus Christ. That means those who believe that do not believe that the dead in Christ or the children of the devil (unsaved) go to Heaven/Hell after they die.
When scripture talks of the death of a saint as being in sleep, it is always speaking of the body, not the soul of the person.
John 11:11 "These things said he: and after that he saith unto them, Our friend Lazarus sleepeth; but I go, that I may awake him out of sleep. 12 Then said his disciples, Lord, if he sleep, he shall do well. 13 Howbeit Jesus spake of his death: but they thought that he had spoken of taking of rest in sleep. 14 Then said Jesus unto them plainly, Lazarus is dead."
In the above passage, Lazarus is dead, but Christ refers to him as being in "sleep". We read that Jesus later on raises Lazarus' BODY.
It is proven also by the next verse that sleep refers to the body and not the soul. In clear English it says that the BODIES were asleep. Their souls were in Abraham's Bosom and that's why Jesus Christ had to go get them and bring them up to Heaven with Him after He died on the Cross.
Matthew 27:52 "And the graves were opened; and many bodies of the saints which slept arose,"
In the New Testament after the Cross, the saint's soul goes straight to Heaven when he/she dies, but in the Old Testament before the Cross, the Old Testaments saint's soul went to Abraham's Bosom. Abraham's Bosom/Paradise was located in the center of the earth across from Hell (Luke 16).
Paul taught that when a person died that his soul was present with the Lord right after death. The heresy of Soul Sleep is destroyed by just simply reading the Bible. The below verses teach that the soul is immediately transfered to the third heaven when a person dies (2 Cor. 12:2).
Philippians 1:23 "For I am in a strait betwixt two, having a desire to depart, and to be with Christ; which is far better:"
2 Corinthians 5:8 "We are confident, I say, and willing rather to be absent from the body, and to be present with the Lord."
This next verse refers to being alive or dead (sleep). When someone dies the body sleeps (Acts 7:60, Matt. 27:52), but the soul does not (1 Thess. 4:14). We are alive "with him" after death. At death, the soul departs from the body (Gen. 35:18, 2 Tim. 4:6, 2 Cor. 5:1-7).
1 Thessalonians 5:10 "Who died for us, that, whether we wake or sleep, we should live together with him."
The last verse that I will use to debunk the false doctrine called Soul Sleep is in the book of Revelation. Here we read of the souls of Martyrs crying out to God. Their bodies were dead, but their souls were in Heaven and not asleep. When one takes the time to read the Bible, he will see that the doctrine of Soul Sleep is absurd.
Revelation 6:10 "And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth?"