I've heard two teachings about this subject. I've heard that a Christians spirit goes directly after death to be with Jesus and awaits the resurrection of the body and I've heard of soul sleep where a Christian sleeps in the ground until the resurrection and the time from death till resurrection is instantaneous. Which is truth? Why or why not?
In the New Testament we read:
Matthew 10:28
28 And do not fear those who kill the body but cannot kill the soul. But rather fear Him who is able to destroy both soul and body in hell.
This verse makes a clear distinction between the physical body and the soul and teaches that it is possible to kill the body without killing the soul.
Revelation 6:9-10
9 When He opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony which they held.
10 And they cried with a loud voice, saying, "How long, O Lord, holy and true, until You judge and avenge our blood on those who dwell on the earth?"
The souls crying out from under the altar are the souls of those who have been slain. Again, this indicates that the soul can exist independently of the body in a conscious state.
Luke 23:46-47
46 And when Jesus had cried out with a loud voice, He said, "Father, 'into Your hands I commit My spirit.' "Having said this, He breathed His last.
47 So when the centurion saw what had happened, he glorified God, saying, "Certainly this was a righteous Man!"
The word "spirit" here is translated from the Greek word "pneuma," which has a variety of meanings in Scripture: wind, breath, life-spirit, soul, the spirit as part of the human personality, the spirit of God, the spirit of Christ, and the Holy Spirit. Context rules out most of these meanings. It doesn't make sense for Jesus to commend his "wind" or "breath" to the Father. It doesn't make any better sense for Jesus to be committing "the spirit of God" or the "Holy Spirit" to the Father. From a plain reading of the passage it is clear Jesus is committing his immaterial human soul or spirit to the Father.
Acts 7:59
59 And they stoned Stephen as he was calling on God and saying, "Lord Jesus, receive my spirit."
If spirit means the life-force within Stephen that ceases to exist when the body dies, then Stephen's request here makes no sense. If this is the meaning of spirit, there is nothing for God to receive. Clearly, Stephen believed his spirit would survive the death of his body and be received by God.
1 Thessalonians 4:13-17
13 But I do not want you to be ignorant, brethren, concerning those who have fallen asleep, lest you sorrow as others who have no hope.
14 For if we believe that Jesus died and rose again, even so God will bring with Him those who sleep in Jesus.
15 For this we say to you by the word of the Lord, that we who are alive and remain until the coming of the Lord will by no means precede those who are asleep.
16 For the Lord Himself will descend from heaven with a shout, with the voice of an archangel, and with the trumpet of God. And the dead in Christ will rise first.
17 Then we who are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air. And thus we shall always be with the Lord.
"...the term "sleep" is always applied in Scripture to the body alone, since in death the body takes on the appearance of one who is asleep. But the term soul sleep is never found in Scripture. And no where does the Scripture state that the soul ever passes into a state of unconsciousness." -
Reasoning from the Scriptures with Jehovah's Witnesses, pg. 314.
Who is God bringing with Him on the Day of Resurrection? Those who "sleep in Jesus." That is, the souls of those whose bodies are "sleeping" in the grave and are about to be resurrected. And when the Lord shouts with the voice of the archangel and the trumpet of God, those bodies that are "dead in Christ" rise first, reunited with the souls of those whom God has brought with Him. Again, we see here that the soul survives the death of the body and goes on to dwell with God.
Luke 20:37-38
37 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.'
38 For He is not the God of the dead but of the living, for all live to Him."
As Jesus points out here, Moses believed that Abraham, Isaac, and Jacob were not dead and gone, but living because God is "not the God of the dead but of the living." Jesus here directly refutes the belief of the Sadducees, which was that the soul died with the body. And he was not merely asserting that God was God over those to be later resurrected.
"Though the dead seem to us to be completely non-existent, they are actually living as far as God is concerned. Note that the tense of the word "live" is not future (which might suggest only that these dead will live at the time of their resurrection) but present, teaching us that they are living now. This holds true not only for the patriarchs but for all who have died. To suggest, now, that Abraham, Isaac, and Jacob are nonexistent between death and the resurrection violates the thrust of these words, and implies that God is, with respect to these patriarchs, for a long period of time the God of the dead rather than the God of the living." - Reasoning from the Scriptures with Jehovah's Witnesses, pg. 316.
Philippians 1:21-23
21 For to me, to live is Christ, and to die is gain.
22 But if I live on in the flesh, this will mean fruit from my labor; yet what I shall choose I cannot tell.
23 For I am hard pressed between the two, having a desire to depart and be with Christ, which is far better.
How could being dead and thus non-existent be "gain" to Paul? Clearly, he did not think the "gain" of which he was speaking was the extinction of his soul with the death of his body, but the departure of his soul from his body to be with Christ. And Paul is not speaking here of a future resurrection. The aorist infinitive ("to live") is linked by a single article with a present infinitive ("to be with Christ"). Thus the infinitives belong together.
"The single article ties the two infinitives together, so that the actions depicted by the two infinitives are to be considered two aspects of the same thing, or two sides of the same coin." -
Reasoning from the Scriptures with Jehovah's Witnesses, pg. 317.
2 Corinthians 5:6-8
6 So we are always confident, knowing that while we are at home in the body we are absent from the Lord.
7 For we walk by faith, not by sight.
8 We are confident, yes, well pleased rather to be absent from the body and to be present with the Lord.
The structure of these verses in the Greek communicates very clearly that Paul understood that dying (being absent from the body) meant being present with the Lord. And the word "with" in Greek suggests very close face-to-face fellowship or intimate relationship.