Let’s examine all New Testament verses which contain the word Hades. The following are from the NKJV (bolding mine):
Mt 11:23 “And you, Capernaum, who are exalted to heaven, will be brought down to Hades ; for if the mighty works which were done in you had been done in Sodom, it would have remained until this day.
Mt 16:18 “And I also say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it.
*Lu 10:15 “And you, Capernaum, who are exalted to heaven, will be brought down to Hades *
Lu 16:23 “And being in torments in Hades, he lifted up his eyes and saw Abraham afar off, and Lazarus in his bosom.
Ac 2:27 For You will not leave my soul in Hades , Nor will You allow Your Holy One to see corruption.
Ac 2:31 “he, foreseeing this, spoke concerning the resurrection of the Christ, that His soul was not left in Hades, nor did His flesh see corruption.
Re 1:18 “I am He who lives, and was dead, and behold, I am alive forevermore. Amen. And I have the keys of Hades and of Death.
Re 6:8 So I looked, and behold, a pale horse. And the name of him who sat on it was Death, and Hades followed with him. And power was given to them over a fourth of the earth, to kill with sword, with hunger, with death, and by the beasts of the earth.
Re 20:13 The sea gave up the dead who were in it, and Death and Hades delivered up the dead who were in them. And they were judged, each one according to his works.
Re 20:14 Then Death and Hades were cast into the lake of fire. This is the second death.
Hades and Gehenna cannot be the same thing, since Gehenna is the Lake of Fire, and Re 20:14 indicates that the writer saw in his vision Hades being cast into the Lake of Fire.
I suggest that “Hades” is simply “the grave.” None of the verses containing the word indicate anyone being conscious in Hades except Luke 16:23, in which Jesus gives a parable based on a common belief of the Jews in His day—that those who die go to a physical place which they called “Hades.” In all other verses it is clearly “the grave.” 'Even Acts 2:27 in which translators render ψυχη as “soul” whereas the word actually means “self.” The sentence “You will not leave my soul in the grave” is a promise of my resurrection.
Jesus also gave a parable of the rich man who talked to his “soul” (actually he talked to himself or “his self”).
Now examine the passages that contain the word “Gehenna” often translated as “Hell.”
Mt 5:22 “But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, ‘Raca!’ shall be in danger of the council. But whoever says, ‘You fool!’ shall be in danger of hell fire.
Mt 5:29 “If your right eye causes you to sin, pluck it out and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell .
Mt 5:30 “And if your right hand causes you to sin, cut it off and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell .
Mt 10:28 “And do not fear those who kill the body but cannot kill the soul. But rather fear Him who is able to destroy both soul and body in hell .
Mt 18:9 “And if your eye causes you to sin, pluck it out and cast it from you. It is better for you to enter into life with one eye, rather than having two eyes, to be cast into hell fire.
Mt 23:15 “Woe to you, scribes and Pharisees, hypocrites! For you travel land and sea to win one proselyte, and when he is won, you make him twice as much a son of hell as yourselves.
Mt 23:33 “Serpents, brood of vipers! How can you escape the condemnation of hell?
*Mr 9:43 “If your hand causes you to sin, cut it off. It is better for you to enter into life maimed, rather than having two hands, to go to hell, into the fire that shall never be quenched — *
*Mr 9:45 “And if your foot causes you to sin, cut it off. It is better for you to enter life lame, rather than having two feet, to be cast into hell, into the fire that shall never be quenched — *
*Mr 9:47 “And if your eye causes you to sin, pluck it out. It is better for you to enter the kingdom of God with one eye, rather than having two eyes, to be cast into hell fire — *
Lu 12:5 “But I will show you whom you should fear: Fear Him who, after He has killed, has power to cast into hell; yes, I say to you, fear Him!
Jas 3:6 And the tongue is a fire, a world of iniquity. The tongue is so set among our members that it defiles the whole body, and sets on fire the course of nature; and it is set on fire by hell.
So we can see that Gehenna or “hell” is a fiery place to which some people go after their death.