There are only 2 possible eternal destinies for every person - either (1) a state and place of everlasting life and blessedness in God’s Presence, for those who have received Christ as their Saviour and Lord, or (2) a state and place of everlasting punishment, for those who have rejected Christ and His offer of Salvation. Every man's final destiny is fixed by God at the time of his death, according to the condition of his soul in relation to God (Ecclesiastes 11:3). There is a HEAVEN to gain and a HELL to shun!
Before the Death and Resurrection of Christ, at death both believers and unbelievers went down to a place called ‘Hades’ (in Greek) or ‘Sheol’ (in Hebrew), a place under the earth for departed spirits, but the believers and unbelievers went to 2 different compartments of Hades, separated by the Bottomless Pit. This is revealed by the true story of the Rich Man and Lazarus (Luke 16:19-26). Before the New Covenant it was impossible for anyone to be born again, and so it was impossible for their spirits to go into Heaven. But now through Christ's death and resurrection, the New Birth is available, which means that when believers die now, our spirits can go straight up to Heaven, because our spirits have been changed, born again, and made perfect in Christ. When Christ rose from the dead, He made the spirits of the Old Testament saints perfect by giving them the New Birth, and then took them to Heaven with Him, so they are there now.
Jesus promised that believers in the Church Age would not go down to Hades, but up to Heaven for they are now in the Kingdom of God (Matthew 16:18, John 3:3-6). Derek gives a number of scriptures that prove that believers now go up ti Heaven when they die.
On the other hand, unbelievers still go down to Torments in Hades, a temporary place of punishment for their soul, because they died in their sins and are guilty. They rejected the grace of God, the work of Christ and the witness of the Holy Spirit. They must wait in this temporary holding-cell in Hades until they are resurrected at the end of time and made to stand before the Great White Throne for their final sentencing and dismissal into the Lake of Fire (Revelation 20), which is their final and everlasting place of punishment, for both their body and their soul (Matthew 10:28).