The Second Death
“He that hath an ear, let him hear what the Spirit saith unto the churches; He that overcometh shall not be hurt of the second death.” (Rev 2:11 KJV)
The second death refers to the eternal punishment in the lake of fire.
“And death and hell were cast into the lake of fire. This is the second death.” (Rev 20:14 KJV)
“But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.” (Rev 21:8 KJV)
The second death is for the devil and those that were not found in the book of life.
“And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.” (Rev 20:10 KJV)
“And whosoever was not found written in the book of life was cast into the lake of fire.” (Rev 20:15 KJV)
Those that overcome will escape the second death.