Adventist believe the "lake of fire" described in Revelation is the ultimate destiny of the wicked. It is the Hell/Hades we find where the wicked will meet their ultimate fate and are punished with eternal separation from God as they perish. The lake of fire is the Second Death from which the wicked meet their end which scripture shows happens at the end of the thousand years of the Millennium..
Revelation 20:7-9
7 And when the thousand years are expired, Satan shall be loosed out of his prison,
8 And shall go out to deceive the nations which are in the four quarters of the earth, Gog, and Magog, to gather them together to battle: the number of whom is as the sand of the sea.
9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from God out of heaven, and devoured them.
The wicked perish in the fire from God after the thousand year reign of Christ with His saints in heaven, all those who have not received the mark of the beast or its image scripture shows.
We see the words of Christ Himself of what will happen to the wicked at the end in the lake of fire/Hell/Hades...
Matthew 7:13 King James Version (KJV)
"13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:"
Matthew 10:28 King James Version (KJV)
"28 And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell."
Matthew 13:40-42 King James Version (KJV)
"40 As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world. 41 The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity;
42 And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth."
Matthew 25:41 King James Version (KJV)
"41 Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:"
We have to repent or we shall perish as is see here, and how will the wicked perish is shown above, thrown into the lake of fire...
Luke 13:3 King James Version (KJV)
"3 I tell you, Nay: but, except ye repent, ye shall all likewise perish."
And Christ gives us eternal life...
John 3:14-16 King James Version (KJV)
"14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up:15 That whosoever believeth in him should not perish, but have eternal life.16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
The wicked will be separated from God forever and ever, it is the end of sin and sinners as they will be destroyed and perish in the lake of fire.
But the saints have nothing to fear, Christ will take the saints to heaven when He comes at the Second Coming as He promised.
John 14:1-3
1 Let not your heart be troubled: ye believe in God, believe also in me.
2 In my Father's house are many mansions: if it were not so, I would have told you. I go to prepare a place for you.
3 And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also.
Revelation 20:4
And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.
Revelation 20:7-9
7 And when the thousand years are expired, Satan shall be loosed out of his prison,
8 And shall go out to deceive the nations which are in the four quarters of the earth, Gog, and Magog, to gather them together to battle: the number of whom is as the sand of the sea.
9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from God out of heaven, and devoured them.
The wicked perish in the fire from God after the thousand year reign of Christ with His saints in heaven, all those who have not received the mark of the beast or its image scripture shows.
We see the words of Christ Himself of what will happen to the wicked at the end in the lake of fire/Hell/Hades...
Matthew 7:13 King James Version (KJV)
"13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:"
Matthew 10:28 King James Version (KJV)
"28 And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell."
Matthew 13:40-42 King James Version (KJV)
"40 As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world. 41 The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity;
42 And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth."
Matthew 25:41 King James Version (KJV)
"41 Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:"
We have to repent or we shall perish as is see here, and how will the wicked perish is shown above, thrown into the lake of fire...
Luke 13:3 King James Version (KJV)
"3 I tell you, Nay: but, except ye repent, ye shall all likewise perish."
And Christ gives us eternal life...
John 3:14-16 King James Version (KJV)
"14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up:15 That whosoever believeth in him should not perish, but have eternal life.16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
The wicked will be separated from God forever and ever, it is the end of sin and sinners as they will be destroyed and perish in the lake of fire.
But the saints have nothing to fear, Christ will take the saints to heaven when He comes at the Second Coming as He promised.
John 14:1-3
1 Let not your heart be troubled: ye believe in God, believe also in me.
2 In my Father's house are many mansions: if it were not so, I would have told you. I go to prepare a place for you.
3 And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also.
Revelation 20:4
And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.