In the beginning when God created Adam and Eve. He told them not to eat that one fruit of the tree. He said if you do you will die. That was spiritual and physical death. They both had to run and hide after that. Before that they were walking and talking with God. That disobedience cost them the fellowship with God. That is spiritual death. Physical death slowly came but they died physically as well.

That spiritual death can only be recovered through another Adam like person who is born without sin and lives without sin. An innocent and sinless person alone can atone for the sins of others. Jesus had to be born through a virgin in order to be human. Yet he needed to be sinless so the conception was caused by the Holy Spirit and not a man in Mary.

When Jesus was born he was sinless and free of inherited corruption of human race just like Adam. Adam and Eve were created pure and without sin.

Now Christ also had to live without any sin. Adam and Eve walked without sin for a while and then sinned and lost the position and fellowship with God.

God had initially commanded them to have dominion over the rest of creation on the earth. They were to be fruitful, multiply, have dominion and rule over them all. When they sinned they lost that position of control and dominion and guess who took over? Satan did. Now God had to send himself to rescue us from that predicament. so Jesus came to earth in human flesh.

He cannot die as God for our sins. But as human he can fit perfectly the requirements of God to justify and atone for our sins. Now he could have sinned but he did not. People accuse him saying that he was God that is why he did not sin. This is a wrong assumption. The bible very clearly tells us that he was human and was tempted in all areas just like us but did not sin. He was human 100% while on the earth and proved to be the ideal candidate to die for the sins of the human race.

Now what happens after he died and gave up his life voluntarily and willingly? He did not stay dead in paradise but God raised him on the third day to prove God had to power to resurrect the dead. HE was the first fruit. One day all who have died will come to life when face the judge of all. Believers or unbelievers in Jesus Christ will all rise from the dead on that appointed day.

Those who accepted the gift of salvation by the death of Christ will attain eternal life and those who rejected will experience eternal hell and lake of fire for ever. It is eternal from that point on and no one can do anything about it. It is irrevocable from that point on.

So the only chance to make that final destination sure is while on earth. Those accept the message of the cross and salvation offered in Christ can seal their eternal destiny. They also spend the rest of their days living in fellowship with God here on earth.