The doctrine of inherent soul immortality and eternal hell torment paints a very different picture of God's character and when people have the wrong conception of God and his character, this leads to a religion of fear and this doesn't please God. "For God has not given us the spirit of fear; but of power, and of love, and of a sound mind" 2 Timothy 1:7. Theologically sound Christianity would point us to Christ's sacrifice and would have us respond to God's Spirit of grace.
Eternal Life is a gift to those who believe:
The case for conditional soul immortality
The Hebrew word for "soul" (nephesh) refers to "the state of being alive" or "life" itself (Gen. 9:4, 1 Kings 17:21-22), this includes all animal life (Gen. 1:24).
According to Hebrew scripture, God formed man out of the dust of the ground, breathed into his nostrils the breath of life, and man became a "living soul", which means man wasn't given a soul, he is a soul (Gen. 2:7). Hebrew scripture also says all life has one breath (Ecclesiastes 3:19). It was doubt in God's word that lead the human race into the curse of sin and death, but it's by faith in God's Word made flesh we have eternal life (Genesis 2:17, Genesis 3:1-5, 17, John 1:14, John 3:16, Romans 5:12, Romans 6:23).
We seek immortality and eternal life because we don't have it (Romans 2:7). Eternal life is a gift of God himself, He alone has immortality (Romans 6:23, 1 Timothy 6:13-16).
The Sleep of Death
At death, dust returns dust (Genesis 3:19, Ecclesiastes 3:20) and the spirit of life in our nostrils returns to God who gave it (Job 27:3–4, Ecclesiastes 12:7).
When someone dies, their thoughts cease (Psalm 146:4). The living know they will die, but the dead aren't conscious of anything (Ecclesiastes 9:5).
The dead remain "asleep" in their graves and they don't come back to haunt us nor do they watch over out shoulders (Psalm 13:3, Job 14:10–12, Job 7:9–10, Job 14:21). Think about this: wouldn't it be unfair if our dead loved ones had a conscious existence and yet weren't allowed to intervene in our lives? What kind of God would allow such a thing? Good thing death is a sleep. Even Jesus compared death to a sleep (Matthew 9:24).
The Redemption of our bodies at Christ's second advent
The dead who sleep in the dust of the earth will soon awake, some to everlasting life, and some to face the second death in which there is no resurrection. (Daniel 12:2, Revelation 20:14). It is appointed unto men once to die, but after this the judgment. (Hebrews 9:27).
Those who believe in God's Word have the hope of the resurrection of the body made incorruptible at the Second coming (Job 19:25-26, Daniel 12:2, 1 Thessalonians 4:13-18, 1 Corinthians 15:50-58).
The creation itself even awaits our redemption so that it may be freed from curse of sin that humankind brought upon it (Romans 8:18-25). The Earth will be made new and there in will be no more suffering from the curse of sin and death (Revelation 21:1, 4, Revelation 22:3).
The Deception of Necromancy
Attempting to contact the "familiar spirits" of the dead is a forbidden practice (Deuteronomy 18:10-11). In the case of the Witch of Endor, we find out that these "spirits" are referred to as "gods ascending out of the earth" which trick our perceptions (1 Samuel 28:13–14).
Human memories are recorded into a book of remembrance, possibly by angels (Malachi 3:16, Ezekiel 9:3-4). With this in mind, then wouldn't it be also possible for lying spirits to use this recorded memory in order to impersonate as the dead? Why, they have nothing better to do than to roam around looking for people to ensnare (1 Peter 5:8). The belief in an inherently immortal soul is the basis for necromancy and whose who hold such belief actually open themselves to it, especially during Near Death Experiences. NDEs are real experiences, but people who have them tend to be quick to make assumptions about death and that the spirits they encounter are who they claim to be. The reality is, these spirits will say whatever people want to hear, even contradicting the bible.
What did Paul mean by "Absent from the body, present with the Lord"?
When the saved are absent from the current body, they will be present with the Lord in the new body which is given to them at their resurrection (2 Corinthians 5:8, 1 Corinthians 15:52). This is why Jesus says that those who believe in him never die (John 11:26).
No one ascends to heaven until Jesus returns, for He holds the keys of death and the power to resurrect the dead. (John 3:13, John 14:2-3, Revelation 1:18, John 11:25). At the second coming, the dead in Christ will be raised with incorruptible bodies and those in Christ who are alive at his coming will meet them in the air (no doubt also with immortal bodies) and so shall we be ever be with the Lord (1 Corinthians 15:52, 1 Thessalonians 4:16-17).
What About The Thief on the Cross?
First, remember that Greek didn't have punctuation. Second, it's also possible that the repented thief died after sunset, thus not the very same day according to the Jewish rendition of time. Jesus had died first and we don't know how much later the soldiers eventually broke the thief's legs (Luke 23:43, John 19:32-33). Lastly, Jesus Himself said himself that he would be in the heart of the earth for three days and He also didn't present Himself before the Father until after His resurrection (John 20:17, Matthew 12:40).
Truth about hell
The New Testament also refers to the soul as mortal (Revelation 6:9, Revelation 16:3). Jesus indeed said not to fear them that killed the body, but to fear Him who can destroy both the body and the soul in hell (Matthew 10:28).
A lake of divine fire is prepared for the devil and his angels, but the devil likes to have human company to go along with him in his rebellion against God's kingdom, even at God's very presence (Matthew 25:41, Revelation 20:9-10). However, this doesn't end well, obviously. They will be annihilated by fire from heaven, becoming as stubble, leaving no trace behind. (Matthew 13:40, Revelation 20:9, Malachi 4:1). Death and hell (hades) will ultimately be cast away into this fire, this is called the second death (Revelation 20:11-15). This Greek word hades translated as "hell" simply means "the grave".
The punishment of the lost is reserved for the day of judgment at the end of the world (2 Peter 2:9) and there is a reason for this.
While it's true that hell fire will burn day and night, each soul burns to death at a different rate because they will be punished justly according to their works. Jesus Himself said: "he that knew not, and did commit things worthy of stripes, shall be beaten with few stripes. For unto whomsoever much is given, of him shall be much required: and to whom men have committed much, of him they will ask the more." Luke 12:48. All souls belong to God who made them and the soul that sins will die, for indeed He can surely destroy both body and soul (Ezekiel 18:4, Matthew 10:28).
James speaks of the destruction of Sodom as an example of ultimate punishment of eternal fire (Jude 1:7), eternal because God's presence is eternal and a consuming fire. (Hebrews 12:29). Revelation 20 describes hell fire as a physical event after the 1000 years in which the wicked will be presented physically alive before the physical throne of God and then cast into the lake of fire. This is contrary to the popularized myths people preach about hell today.
However, God makes an appeal to us saying, "I have no pleasure in the death of the wicked, but that the wicked turn from his way and live. Turn, turn from your evil ways! For why should you die, O house of Israel?" (Ezekiel 33:11).The Rich Man and Lazarus
Many point to the parable of the rich man and Lazarus to prove that souls are inherently immortal, but Jesus was simply using a Greek allegory to explain that the rich are not necessarily blessed and that if they would not believe Moses and the prophets, a resurrection would not convince them (Luke 16:19-31). The law (Torah) and the prophets do not teach an immortal soul, but there is a hope for the resurrection of the body (Daniel 12:2). The Jews, or at least the Pharisees believed in a resurrection, but many refused to believe in Jesus who is the resurrection and the life (Daniel 12:2, Acts 23:8, John 11:25).
What about the Worm that Doesn't Die?
Jesus referred to a place called "Gehenna" (translated as hell) where the worm doesn't die and many claim this is referring to the soul (Mark 9:44). First of all, Jesus was quoting from prophecy in Isaiah referring to literal worms eating the cadavers of transgressors (Isaiah 66:24). Second, this place called Gehenna is also known as the Valley of Hinnom and it is referred to as a place where people used to make their children walk through fire and God says he will punish people who do such things with fire (Jeremiah 7:31-32, Isaiah 30:33). Jesus was using this as an example of what the Lake of fire would be like. Interestingly, in the very previous verse of the one Jesus had quoted, it portrays other people looking over at the cadavers and keeping His Sabbaths! How many Christians keep the biblical Sabbath?