What happens to us after we die? Do we simply cease to exist? Many people believe it either goes black, we go to "sleep," we get our galaxy, or we reincarnate into something else. To start we must ask the question of why we die or why there is death at all. The answer to that is in the book of Genesis where Adam chose to disobey God's commandment to not eat the fruit. Because of sin, God had to punish Adam to be just. And that punishment is "Cursed is the ground because of you; through painful toil, you will eat food from it all the days of your life" (Genesis 3:17). 

Genesis 3:6-7 "6 When the woman saw that the fruit of the tree was good for food and pleasing to the eye, and also desirable for gaining wisdom, she took some and ate it. She also gave some to her husband, who was with her, and he ate it. 7 Then the eyes of both of them were opened, and they realized they were naked; so they sewed fig leaves together and made coverings for themselves."


Scripture clearly states that “The dust returns to the ground it came from, and the spirit returns to God who gave it.” To those who are redeemed and have their sin forgiven, God gives eternal life. It is appointed for us to die once, and after that will come judgment.

Hebrews 9:27
"And just as it is appointed for man to die once, and after that comes judgment"

Those who have rejected Christ as Savior will be sent to eternal punishment in hell (Matthew 25:46).
Hell, like heaven, is a literal place. It is a place where the unrighteous will experience the never-ending, eternal wrath of God.

if we choose to reject Christ we also reject the heaven that He has prepared. Realize that I say "We Choose To Reject." A big part of choosing is knowing that God will not force us into submission. If you choose to reject Christ, This also means you stand condemned already. 

Another question when it comes to DEATH is the topic of complete annihilationism.
Is annihilationism biblical?

Annihilationism is the belief that unbelievers will not experience an eternity of suffering in hell, but will instead be “extinguished” after death. Some passages seem to argue for this belief, but is it true? There are three points in which to look at when it comes to annihilationism:
1) The nature of hell
2) The consequences of sin
3) The justice of God

So let's start with the first misunderstanding: The nature of hell.
annihilationists misunderstand the meaning of the lake of fire. It is not simply a human body being cast into the lake of fire. Humans are made of three things, body, soul, and spirit. Can a spirit and soul be consumed or destroyed by physical fire? No. A spiritual nature cannot be consumed by physical fire. Even the unsaved will be resurrected with a body in which will be prepared for eternity just like we as believers are also. These bodies are prepared for an eternal fate. Either Heaven or Hell.

The second misunderstanding: Eternity.
the Greek word 'aionion' is translated as “eternal,” which does not by definition mean “eternal.” However, it is clear that in the New Testament, onion is sometimes used to refer to an eternal length of time. When we look at certain scriptures that speak of eternity, we can see that it means forever. In Revelation 20:10 it reads that "they will be tormented day and night forever and ever." So why would the fate of the unbeliever be any different? Look at Revelation 20:14–15 "if anyone’s name was not found written in the book of life, he was thrown into the lake of fire."

The third misunderstanding: The justice of God.
How is it fair for God to take a person who lived a sinful life, and punish them for all eternity?
Let's look at King David when he committed the sins of adultery and murder and when he stated, “Against you, you only, have I sinned and done what is evil in your sight” (Psalm 51:4). David knew he had sinned against Bathsheba and Uriah. In scripture, David claimed to have only sinned against God? The answer is that David understood that all sin is ultimately against God. God is an eternal and infinite Being. We need to understand that all sin against God is worthy of eternal punishment. It's the character of God against whom we sin against.