What is “soul”? This needs to be addressed before knowing whether it is “mortal or immortal”. Analysis is critical in understanding this concept of the word “soul” used to translate in English, the Hebrew word “nephesh” and the Greek word “psyche”. To do this, one has to go back to Genesis and take us through the step-by-step mechanism in the formation/creation of man.
“And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath (nhshamah) of life (chay); and man became a living soul(nephesh).” (Gen. 2:7). Notice here that “nephesh” was translated “soul”
As the preceding verse connotes, man was formed from “dust of the ground”, matter-composed. Whereas, the “breath of life” came from God, who did not use “matter” like “dust of the ground”, and therefore spirit-composed. What was formed from “dust of the ground” was the “lifeless” physical body, viz., brain, heart and other parts of the body. This “lifeless body” became alive only when God “breathed into his nostrils this “spirit-composed breath of life”. Then and only then did man become a”living soul”, a “nephesh” or breathing creature. Meaning, body+breath of life=”living soul”; nephesh/breathing creature.
This tells us that a living being(human) has 2 components, viz., body and breath of life before being classified or called as a “living soul/nephesh”. In Biblical parlance, one can deduce to a certain extent that the English word “soul” in the O.T. refers to a “living being/human”. The “body” has to be alive to be called “soul”(nephesh/breathing creature), hence the emphasis on the descriptive phrase “living soul” in Gen. 2:7. Otherwise, the body without the “breath of life”(nshamah chay) is “lifeless”. Nephesh or living creature/soul is a composite of “body(soma) and breath of life(nshamah).
Proof of these two separate components can be derived from the fact that each one can be destroyed or killed, as in:
Matthew 10:28 “And fear not them which kill the body(soma), but are not able to kill the soul(psyche): but rather fear him which is able to destroy both soul(psyche) and body(soma) in hell(Gehenna).” Notice that “breath of life”, Hebrew “nshamah chay” in Old Testament, is Greek “psyche” in New Testament and equivalent in English to “soul”.
Strictly speaking and to prevent misunderstanding, the English translation “soul” should have been limited by the “translator” and only be specifically applied to “living creature”(nephesh) composed of body/soma and psyche/ human spirit as the translated word “soul” does not accurately convey the actual reference to the 2 separate components of man.
From the above statements, it is clear that this “breath of life/psyche/nshamah”, which is part or a component of a “living being/soul”, is not “immortal and can be killed. Notice though that the “breath of life/psyche/nshamah” at death(reversible as it is temporary) goes back to the Creator although can be killed in Gehenna fire, an irreversible/permanent death. It is the “soma/body/dust” that goes to the grave/hades/hell. Nevertheless, when we die and “thoughts perish”, the “soma/body/dust” is buried in hell/hades/grave and subsequently rots, but the “breath of life/psyche/nshamah” at time of death (reversible) goes back to the Creator, as in:
Ps.146:4 “His breath (ruwach) goeth forth, he returneth to his earth; in that very day his thoughts perish.” (No longer thinking when dead; no consciousness)
Ezekiel 18:4 “…the soul (living being) that sinneth, it shall die”. ( soul is not immortal)
Eccl.12:7 “Then shall the dust (aphar/clay/the body) return to the earth as it was: and the spirit (ruwach or breath in O.T and psyche in N.T) shall return unto God who gave it.”
Notice that, while the “soul”(spirit/breath of life/psyche) can be killed or destroyed, at death it goes back temporarily to the Creator” to wait for a future body at time of “resurrection”. From there, it will be given a “spirit-composed body” to those participating at the time of 1st resurrection and together with Jesus coming back at the start Millenium on earth. And we, who are alive in the “flesh” on this resurrection day will change “in a twinkling of an eye” (ICor. 15:52) from mortal to immortal (I Cor. 15:53-54), and meet Jesus and the rest of the “firstfruits” “in the air” (I Thes.4:17) to come down to earth and to the temple in Jerusalem. From here, Millenium starts and the “kingdom of God” like a “stone” (Dan.2:35) will subsequently occupy the whole earth. Those who will participate in the “second resurrection” will have a “flesh-mortal body”, not immortal, and will experience the in-dwelling of the Holy Spirit, bear “fruits of the Spirit” and be given subsequently an immortal body. Those who still reject this promise of the Holy Spirit will be thrown in “Gehenna fire” to suffer “eternal and irreversible death”.
I did not understand this concept until I learned about computer technology. The parallel is: The spirit (psyche) of man is much like a “thumb-drive” or USB flash-drive that has all the “memory” or information/data that one can download into, save a copy that goes back to the owner. The whole computer (like our body) can be destroyed or die/rot, but the “breath of life/spirit”, (the memory and history of our unique life) that goes to the Creator, can then be “inputted” into a “new computer”. This new computer maybe “spirit-composed body”, immortal, much like in the “first resurrection” or can be “flesh-composed” as in the “second resurrection” and mortal. As the thumb drive can be destroyed, so can the “spirit/ruwach/breath of life” in Gehenna fire at Judgement Day after the ”second resurrection”.
By the way, the “spirit of man” is different from the “Spirit of God” that Jesus died for and resurrected for us to receive (“to in-dwell in us”) by grace and out of love by the Father. In a computer analogy, the Spirit of God can be equivalent to the “operating system”(O.S.), without which nothing can be “energized” or empowered.
Regarding the following verses from which the concept of “immortal soil” were derived, here are comments for consideration that explain them:
The verses quoted are projections into the future, not current.
Rev.6:9-11 refers to the “slain for the word of God”, their bodies in the grave and psyche/spirit with the Creator. They “should rest yet for a little season”, i.e. avenging is still future. The “psyche” is a component of man that can only function with a body; it has no “immortal bodies” yet, as the promise of first resurrection is still future at the second coming of Christ. Without a body, the “psyche” cannot vocalize. Yet, they appeared to have “cried with a loud voice”. This “cry” can only be understood as an “allegory” to mean an expression of their long time desires since the “psyche” keeps all the “memories and past of the slain”.
Luke 16:19-31 are events at second resurrection. The rich man will be resurrected to flesh, continue to reject the Holy Spirit and will be thrown in the “lake of fire”, “tormented by flame”/ Gehenna fire, a place on earth for “unrepentant sinners”.
Matt 17:1-9 is also future. Notice the words “transfigured”(metamorphoo), aka transformed and “vision”(horama), a supernatural spectacle of the future. In addition, the phrase “his face did shine as the sun, and his raiment was white as the light.” can only be referring to post resurrection, as in:Mark 9:3 ; Luke 9:29; Revelation 3:5; Revelation 3:18; Revelation 4:4; Luke 9:29; Rev. 4:4; Rev. 4:4
And, specifically, those with “white raiment” are “overcomers” (future) as in, Revelation 3:5 “He that overcometh, the same shall be clothed in white raiment;”.
Regarding I Thes.5:23″…pray God your whole spirit(pneuma) and soul(psyche) and body(soma) be preserved…”, the “and” is copulative primary particle, i.e., even, also or the same and consistent with the concept that breath of life is similar to spirit / pneuma or soul/psyche.