What happens when we die?
To understand what happens when we die, we have to understand what the soul is.
And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul. ~ Genesis 2:7
The scriptures tell us that the soul is not something we have inside our bodies. The soul is the person itself. When God created Adam, He didn't give Adam a soul. Adam became a living soul.
We are a soul. That's why we read that souls are born (Genesis 46:18), souls eat (Leviticus 7:20) souls sin (Leviticus 5:17, James 4:4). Souls learn (Proverbs 19:2). Souls can get sick (psalm 41:4) Souls can die (Job 33:22) Souls can be touched and killed (Joshua 11:11, 1 kings 15:29) souls can be buried (psalms 35:7, Jeremiah 18:20). We don't have souls, we are souls.
We (souls) are not immortal or eternal.
Something eternal is something without beginning or end; lasting forever; always existing. Therefore we (souls) can't be eternal, because we were created by God. (Genesis 1). (We have a beginning) and we (souls) can't be immortal because the only immortal is God.
Which in his times he shall shew, who is the blessed and only Potentate, the King of kings, and Lord of lords; Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see: to whom be honour and power everlasting. Amen. ~ Timothy 6:15-16
Therefore we (souls) can't reincarnate, go to heaven, hell, purgatory or to a spiritual world when we die. Souls are not immortal.
Another reason why we (souls) can't be immortal can be found in Ezekiel 18:20:
"The soul that sinneth, it shall die"
We have all sinned.
As it is written, There is none righteous, no, not one: ~ Romans 3:10
For all have sinned, and come short of the glory of God; ~ Romans 3:23
Thankfully the salvation plan of God comes into action here. But that's another topic.
Now that we know what souls are, there's still the question of what happens when we die?
For the living know that they shall die: but the dead know not anything, neither have they any more a reward; for the memory of them is forgotten. ~ Ecclesiastes 9:5
Also their love, and their hatred, and their envy, is now perished; neither have they any more a portion forever in anything that is done under the sun. ~ Ecclesiastes 9:6
Whatsoever thy hand findeth to do, do it with thy might; for there is no work, nor device, nor knowledge, nor wisdom, in the grave, whither thou goest.~ Ecclesiastes 9:10
By the sweat of your face you shall eat bread, till you return to the ground, for out of it you were taken; for you are dust, and to dust you shall return. ~ Genesis 3:19 </i>
For what happens to the children of man and what happens to the beasts is the same</b>; as one dies, so dies the other. They all have the same breath, and man has no advantage over the beasts, for all is vanity. All go unto one place; all are of the dust, and all turn to dust again. ~ Eclesiastés 3:19-20
But if you died in Christ you will be resurrected to live eternally with Him.
(1 Thessalonians 4:14-17)
Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years. ~Revelations 20:6
To resurrect, first we have to die. If we (souls) were immortal the term 'resurrection' shouldn't be used/needed.
Another text we can use to prove that when we die, we don't go to heaven, purgatory, hell, or to a spiritual world is:
Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God. ~ John 20:17
Jesus had been dead for three days. If it were true that we have a soul (as a separate thing from our body) it was only logical that Jesus' soul had ascended to heaven after He died. Yet He said "Touch me not; for I am not yet ascended to my Father".
Therefore when we (souls) die, we rot in the grave until the first resurrection. (The first resurrection will only be for the saved, even though not all saved people will be dead when Jesus comes)
Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed, In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed. ~1 Corinthians 15:51-52
Every single person on this earth (death or alive) will be judged by God; and every single one of us will be/stay dead or alive when the judgment day comes (not everyone will be dead when God starts His judgment).
We cannot go to heaven, hell or purgatory when we die because we haven't been judged.
God has a day in which He will judge us all. (Romans 2:16, 2 Timothy 4:1, Ecclesiastes 12:13-14 )
Because he hath appointed a day, in the which he will judge the world in righteousness by that man whom he hath ordained; whereof he hath given assurance unto all men, in that he hath raised him from the dead. ~ Acts 17:31
Once He finishes judging us all, He will come (Acts 1:11, Matthew 26:64)
And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be. ~ Revelation 22:12
And those whose names are written in the book of life will be saved. It is then that the saved will receive eternal life. The eternal life Adan and Eve lost when they sinned.