Are they literal or symbolic?
Following his sacrifice and resurrection from the dead, Jesus Christ was given all power in heaven and earth.
Matthew 28:18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
He has the power to raise the dead out of their graves and restore them to life.
John 6:39 And this is the Father’s will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day.
This is described metaphorically as having the keys of hell and death.
Revelation 1:18 I am he that liveth, and was dead; and, behold, I am alive for evermore, Amen; and have the keys of hell and of death.
Hell is not the place of eternal torment of Christian mythology. Hell is the translation of the Greek ’hades’ which refers to the grave.
Jesus is God’s appointed judge.
John 5:22 For the Father judgeth no man, but hath committed all judgment unto the Son:
God has appointed a time in the future when Jesus will return to raise and judge the dead.
Acts 17:31 Because he (God) hath appointed a day, in the which he will judge the world in righteousness by that man whom he hath ordained; whereof he hath given assurance unto all men, in that he hath raised him from the dead.
He will raise the dead out of their graves and restore them to life for judgment.
John 5:28 Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, 29 And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation (condemnation).
Those who are rejected will be condemned to die for a second time (the second death) and perish forever.
Jesus will restore the throne of David and establish the kingdom of God upon the earth.
Luke 1:32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
The faithful will be given eternal life and reign with Christ over the mortal population of the earth for 1000 years.
Revelation 20:6 Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
At the end of the millennial reign, there will be a second resurrection and final judgment. Christ will raise and judge those who have died during his millennial reign. ‘Hell’ (the grave) will give up the dead for judgment.
Revelation 20:13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
After this, sin will be eradicated, there will be no more death or need for graves. Death and ‘hell’ – the grave – are metaphorically cast into the lake of fire.
Revelation 20:14 And death and hell were cast into the lake of fire. This is the second death.
The lake of fire isn’t literal, it represents complete destruction. The punishment for sin is death, not eternal torment.
Ezekiel 18:20 The soul that sinneth, it shall die...
Romans 6:23 For the wages of sin is death…
All who live on will possess the divine nature and God will live with, and in, them forever.
2 Peter 1:4 Whereby are given unto us exceeding great and precious promises: that by these ye might be partakers of the divine nature, having escaped the corruption that is in the world through lust.
Paul explains what is going to happen:
1 Corinthians 15:20-28 But now is Christ risen from the dead, and become the firstfruits of them that slept. 21 For since by man came death, by man came also the resurrection of the dead. 22 For as in Adam all die, even so in Christ shall all be made alive. 23 But every man in his own order: Christ the firstfruits; afterward they that are Christ’s at his coming. 24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power. 25 For he must reign (the millennial reign), till he hath put all enemies under his feet. 26 The last enemy that shall be destroyed is death. 27 For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is excepted, which did put all things under him. 28 And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.
This will be the fulfilment of God’s purpose.
Numbers 14:21 But as truly as I live, all the earth shall be filled with the glory of the LORD.
Revelation describes it thus:
Revelation 21:3 And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God. 4 And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away.
I hope you find this helpful.