The fire cannot be put out by human hands. That's why it's unquenchable. But once it consumes and there's nothing but stubble and ash, it will be finished. That is the second "death". That's eternal destruction, which is everlasting. But it will pass away as it's a former thing. Christ states that he will make all things new. That includes no more death, pain, etc. That can't be possible if we still have the LOF with people burning forever. They will burn up.
Malachi 4:1 "For, behold, the day cometh, that shall burn as an oven; and all the proud, yea, and all that do wickedly, shall be stubble: and the day that cometh shall burn them up, saith the Lord of hosts, that it shall leave them neither root nor branch."
Malachi 4:3 "And ye shall tread down the wicked; for they shall be ashes under the soles of your feet in the day that I shall do this, saith the Lord of hosts."
Ezekiel 28:18
"Thou hast defiled thy sanctuaries by the multitude of thine iniquities, by the iniquity of thy traffick; therefore will I bring forth a fire from the midst of thee, it shall devour thee, and I will bring thee to ashes upon the earth in the sight of all them that behold thee."
Matthew 10:28 "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."
II Thessalonians 1:9 "Who shall be punished with everlasting destruction from the presence of the Lord, and from the glory of his power;"
Revelation 20:14 "And death and hell were cast into the lake of fire. This is the second death."
Revelation 21:4 "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."
Revelation 21:5 "And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful."