*Some teach that “Jesus took the keys of hell and death from Satan” when he went to hell to conquer Him. The Bible does not say this at all.
Satan did not steal the keys from Adam because Adam did not ever have them. When Adam and Eve sinned it brought sin and death into the world (Romans 5) and when people go to the grave and are not being with God when they die. There are two separate compartments in Hades, on one side is Paradise, Abrahams bosom on the other side is what we today call hell (sheol) where the unbeliever goes. “And being in torments in Hades, he lifted up his eyes and saw Abraham afar off, and Lazarus in his bosom”(Luke 16:23)

Jesus says in Revelation 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.” Jesus conquered death
 
 This means that everyone one day will be resurrected to face the judgment of Christ and either being with Him or cast away (into the lake of fire).

“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” (Matt 16:18). In other words, they who believe will be resurrected to life, they will not stay dead. Jesus spoke to those who believed in Him, though you may die you will live.

In Rev 1:18 The word is Hades, not hell; the keys are used as an emblem of power and authority. Jesus has full control, he always did.

Revelation 1:18 A.T. Robertson writes- Of death and of Hades tou (NT:3588) thanatou (NT:2288) kai (NT:2532) tou (NT:3588) hadou (NT:86). Conceived as in Matt 16:18 as a prison house or walled city. The keys are the symbol of authority, as we speak of honoring one by giving him the keys of the city. Hades here means the unseen world to which death is the portal. Jesus has the keys because of his victory over death. See this same graphic picture in Rev 6:8; 20:13f. For the key of David see Rev 3:7, for the key of the abyss see Rev 9:1; 20:1. (from- Robertson's Word Pictures in the New Testament).

It is Jesus Christ alone that can save and destroy, can kill and make alive. Death and Hades are still under His dominion, and he can recall the dead whenever he pleases. He is the resurrection and the life. It tells us when the Son of God speaks the graves will open- John 5:25: “Most assuredly, I say to you, the hour is coming, and now is, when the dead will hear the voice of the Son of God; and those who hear will live.”

As Paul makes it clear in1 Corinthians 15:54-55: “So when this corruptible has put on incorruption, and this mortal has put on immortality, then shall be brought to pass the saying that is written: "Death is swallowed up in victory.” “O Death, where is your sting? O Hades, where is your victory?”

Rev 20:11-15: At the White throne judgment after the Millennium “And I saw the dead, small and great, standing before God, and books were opened. And another book was opened, which is the Book of Life. And the dead were judged according to their works, by the things which were written in the books. 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. Then Death and Hades were cast into the lake of fire. This is the second death. And anyone not found written in the Book of Life was cast into the lake of fire.”

What this means is that everyone will be resurrected to face the judgment of Christ and either be with him forever in paradise unspeakable (2 Corinthians 12) or they will not.