Before going into the matter of Hades or hell, we should keep in mind that as God is revealed in the Scriptures as the Triune God, He created man triune, too: spirit, soul, and body (1 The. 5:23; Heb. 4:12) It is the soul of man that separates from the body at the time of death, and this soul goes to one of two places: to be with the Lord Jesus Christ, or to Hades (or hell).
Going to the beginning of creation, we learn that God is a Covenant God. Before the foundation of the world God made an everlasting Covenant with Himself, within the Godhead. God, the Father was going to create a people for Himself; God, the Son was going to redeem these people from death  and God, the Holy Spirit was going to indwell them forever.
That was going to be the work of the Messiah, to redeem a people and to give them the promise of eternal life. That was the Covenant of Promise. That was the Promise that all the saints in the Old Covenant hoped for. They were waiting for this redemption, that the Messiah was going to do. OC saints did not receive the promise, but saw it “afar off”. (Heb. 11:13,39)
The indwelling of the Holy Spirit was also something strange to the saints in the OC. They, only the Jews, were able to know God, because God dwelled in the midst of them in the tabernacle and later in the temple. Only a few special people like priests, prophets and some kings were indwelled by the Holy Spirit. He was not given to everyone. That’s why David cries “do not take your Holy Spirit from me” after he had sinned in Psalm 51. The Holy Spirit was that promise that the saints received at Pentecost. (John 7:37-39)
Also, we learn in the beginning that the sin of Adam brought death and damnation to the human race. Man died after he sinned, and death is the most terrible thing that could have happened to him and us. Now, we all die. Our bodies are destined for corruption and once death comes, judgment will follow. That was the condition of man after the fall. When man rejected God in the Garden of Eden, Satan became the prince of this world. He enslaved man and acquired dominion of Sheol and of death. (Heb. 2:14-15)
Now, we should examine the meaning of the words ‘Sheol’ and ‘Hades’. The word for Hades in the Old Covenant (Testament) is “Sheol” (H7585). The KJV translates ‘Sheol’ as ‘grave’, also as ‘hell’ and ‘the pit’, but if we see the Hebrew, the word used in all these instances is ‘Sheol’. There is actually a different word/s for ‘grave’ in the Hebrew language (H6900, H6912, H6913)
Before the cross, there was one place where all souls of men went after death. Saints and reprobates went down to Sheol. The Lord Jesus Christ explained that this place was separated by a great ‘gulf’ (Luke 16) and no one could pass from one place to the other, but Sheol was within closed iron gates, and Satan had the keys. (Heb. 2:14)
As we continue reading in the OC, we will find that there was never mention of heaven or paradise. The saints who died were all knowledgeable that their souls were going down to Sheol. This word appears sixty-five times in the OC and every time refers to the place where the souls went after death. A place down below inside the Earth. The notion of going to heaven or Paradise after death was the teaching of Christ. John 14:2. Christ had to die to prepare that place for His people.
The first time we encounter the word ‘Sheol’ is in Gen. 37:35 where we read of Jacob mourning for his son Joseph who, he believed, was dead. He said, “I will go down to Sheol unto my son mourning”. Jacob was one of God’s elect, why did he say that he was going down to Sheol to be with Joseph who was also elect? The fact is that all the saints knew that everyone was going to be in Sheol after death.
The meaning of ‘Sheol’ is always a place down below, in the “nether parts of the Earth”. The sad story of Numbers 16, the rebellion of Core, shows how all these wicked men descended into Sheol alive, including their little children. Also, in 1 Samuel 28:13 when Saul uses the woman from Endor to call Samuel from the dead, she said, “I saw gods ascending out of the Earth”. This word ‘gods’ is Elohim, and it should have been translated ‘judge’ because it refers to Samuel, a saint, in this case. So, the saints went to Sheol together with the reprobates.
There was never mention of the saints in the OC going to be with the Lord after death. There are though, many references to Christ going to Sheol or Hades. In the Psalms, which all prophesied of the Messiah, we read, “For you will not leave my soul in Sheol” (Ps. 16:10; 18:5; 49:15; 86:13; 116:3 among many more).
In the New Covenant (Testament) we find that Hades was the Greek word that replaced the Hebrew ‘Sheol’. When Christ was asked for a sign of His Messianic authority, He gave the sign of the prophet Jonas saying, “For as Jonas was three days and three nights in the whale’s belly; so shall the Son of man be three days and three nights in the heart of the earth” (Mat.12:40). What was Christ talking about?
Also, when Christ told Peter, “…upon this rock I will build my church and the gates of Hades shall not prevail against it” (Mat.18:16) What was Christ talking about? He is the only One who can tell us.
Christ had to come to destroy the works of the Devil (1 John 3:8). He died on the cross and went to Hades (Eph. 4:9) to wound the head of the Serpent (Rev. 13:3) as was prophesied in Gen. 3:15. That is the battle that is described in Rev. 12, Michael (Christ) and His angels fought against the dragon and cast him out. That was the sign of the prophet Jonas and that’s why Christ was three days and three nights in the heart of the Earth. Â After that, the Devil didn’t accuse the saints anymore (Job 1), and Christ took His saints from Hades, the dominion of Satan, and translated them to Paradise.
That’s why we read in Mat. 27:53 that many saints rose again after His resurrection. Christ took them out of Hades. That was the first resurrection told of in Rev.20:5. Also, Christ repeats many times in Rev. 1-3 that He has the keys of death and Hades. Christ overcame Satan at the cross. Satan has no more power over Christ’s people to take them to Hades after death. He still has the liberty to go and deceive the nations as he has always done, but he can never deceive the elect of God, because the gates of Hades shall never prevail against the saints, the true church of Christ.
On the other hand, the reprobate was left in Sheol or Hades. They are still there, in torments, awaiting the judgment of the last day. Christ said it very clearly in Luke 16:19, which is a true story that only the Man who came from heaven could tell (John 3:13).
Daniel was the first to talk about the resurrection, “And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt” Dan.12:2
Christ also reiterates it in Mat. 25:46, “These shall go away into everlasting punishment”. In Rev. 14:11 God pours the cup of His indignation upon the two thirds (reprobates) and they “shall be tormented with fire and brimstone…and the smoke of their torment ascends up forever and ever, and they have no rest day nor night”…
So, eternal punishment is real and it will be painfully surprising to many deceived people who believe in the lie of annihilation.