Question: When the Bible refers to "sleep," what does it mean?

Question: “Sleep” seems to be a key word in 1 Thessalonians:4:13-17 [13] But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope. [14] For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him. [15] For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep. [16] For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: [17] Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
See All.... What does “sleep” mean in that context?

Response: The term is actually “which sleep in Jesus” (v. 14). “Sleep” is often used to signify “death”: “the maid is not dead, but sleepeth” (Matthew:9:24He said unto them, Give place: for the maid is not dead, but sleepeth. And they laughed him to scorn.
See All...); “Our friend Lazarus sleepeth; but I go, that I may awake him.” [They thought that he had meant “taking rest” in sleep.] 

“Then said Jesus unto them plainly, ‘Lazarus is dead’” (John:11:11-14 [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.
See All...). Sleep is only necessary for bodies, which tire, but not for souls and spirits. Therefore, “sleep” can only refer to the body that is in the grave awaiting the resurrection. Although the body is dead, the thinking person who once lived in that body is still conscious but now freed from bodily limitations and constraints. The phrase “asleep in Jesus” refers to believers who have died trusting in Christ and are now secure in Him for all eternity.

The rich man’s body lay in the grave, but his “soul and spirit” (1 Thessalonians:5:23And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
See All...; Hebrews:4:12For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
See All...) were conscious in hell and in torment (Luke:16:19-31 [19] There was a certain rich man, which was clothed in purple and fine linen, and fared sumptuously every day: [20] And there was a certain beggar named Lazarus, which was laid at his gate, full of sores, [21] And desiring to be fed with the crumbs which fell from the rich man's table: moreover the dogs came and licked his sores. [22] And it came to pass, that the beggar died, and was carried by the angels into Abraham's bosom: the rich man also died, and was buried; [23] And in hell he lift up his eyes, being in torments, and seeth Abraham afar off, and Lazarus in his bosom. [24] 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. [25] 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. [26] And beside all this, between us and you there is a great gulf fixed: so that they which would pass from hence to you cannot; neither can they pass to us, that would come from thence. [27] Then he said, I pray thee therefore, father, that thou wouldest send him to my father's house: [28] For I have five brethren; that he may testify unto them, lest they also come into this place of torment. [29] Abraham saith unto him, They have Moses and the prophets; let them hear them. [30] And he said, Nay, father Abraham: but if one went unto them from the dead, they will repent. [31] And he said unto him, If they hear not Moses and the prophets, neither will they be persuaded, though one rose from the dead.
See All...). The Christian’s soul and spirit, when separated from the body through death, go immediately into the presence of the Lord (2 Corinthians:5:8We are confident, I say, and willing rather to be absent from the body, and to be present with the Lord.
See All...); “…having a desire to depart, and to be with Christ; which is far better” (Philippians:1:23-24 [23] For I am in a strait betwixt two, having a desire to depart, and to be with Christ; which is far better: [24] Nevertheless to abide in the flesh is more needful for you.
See All...).

Unquestionably, Paul is expressing the desire for his soul and spirit to depart the flesh of his body in order to be with Christ in heaven. And just as obviously, he expects to be conscious in the presence of his Lord. To be “with Christ” could hardly mean anything to someone who was unconscious!

Nor could Paul possibly consider an unconscious state of “soul sleep” to be “far better” than remaining alive to serve Christ and the church! The statement “them which also sleep in Jesus will God bring with him” (1 Thessalonians:4:14For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
See All...) refers to the souls and spirits of believers in Christ whose bodies have been “asleep” in the grave. These souls and spirits have been present with Him in heaven in that “far better” state of “absent from the body, present with the Lord.” Paul declares that the souls and spirits of those who died with faith in Christ are reunited with their resurrected bodies, which are raised to life at the Rapture—then caught up to heaven with those in Christ who have not died but are likewise transformed into Christ’s image at that glorious moment.