Question:Has this become a Christian myth that at the moment of death your spirit goes to Heaven to be with Jesus Christ? My biblical understanding is that your spirit is in the grave and asleep until the resurrection when Jesus calls at the Second Coming.
"Myth" would not be the correct word as the belief is based on quite a number of passages.
The mention of "sleeping" for the idea of death is an idiom in the Scriptures. It doesn't necessarily mean that we literally sleep, but rather indicates that death is not a permanent state. See: "Does the Bible speak of souls sleeping?" for more details. As a matter of fact, the conversation of the rich man with Abraham in Hades indicates that people are not asleep in the sense of being unconscious (Luke 16:19-31)..
Going straight to heaven after death doesn't account for the judgment. See: "When you die, do you go straight to heaven or hell?" for details.
However, there are several passages that have intrigued people over the years. It is noted that after the time of Jesus resurrection, there is mention of the wicked going to Hades (II Peter 2:9-10; Jude 6), but not the righteous. This is tied to Ephesians 4:7-10 where it states that Jesus lead captivity captive by his resurrection. The thought is that in overcoming death, Jesus has altered what happens when a person dies.
Thus, it is pointed out that Stephen prayed, "Lord Jesus, receive my spirit" (Acts 7:59). But Jesus was not in Hades at that time (Acts 2:31-33). Paul spoke of two states, "So we are always confident, knowing that while we are at home in the body we are absent from the Lord. For we walk by faith, not by sight. We are confident, yes, well pleased rather to be absent from the body and to be present with the Lord. Therefore we make it our aim, whether present or absent, to be well pleasing to Him" (II Corinthians 6:5-9). He also applied this personally. "For to me, to live is Christ, and to die is gain. But if I live on in the flesh, this will mean fruit from my labor; yet what I shall choose I cannot tell. For I am hard pressed between the two, having a desire to depart and be with Christ, which is far better. Nevertheless to remain in the flesh is more needful for you" (Philippians 1:21-24). Therefore, the statement of being with Jesus after death is scripturally based.
Finally, there is noted the scene in Revelation, "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. 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?" Then a white robe was given to each of them; and it was said to them that they should rest a little while longer, until both the number of their fellow servants and their brethren, who would be killed as they were, was completed" (Revelation 6:9-11). The martyred are portrayed as being at the base of the altar before God.
There is enough there to cause me to wonder, but as I mentioned earlier, we are told that gaining heaven comes after the Judgment, so I'm not certain how to resolve the idea of being with Christ, who is in heaven, and not entering heaven until after the Judgment. But ultimately, it doesn't matter because it won't change how I live my life on this earth, not will it change the fact that the final destination is heaven no matter how you look at it.