The final place where Satan, his servants, and people who refuse to turn away from evil will stay forever.
The Bible only mentions the lake of fire in the book of Revelation (Revelation 19:20; 20:10, 14–15; 21:8). The book describes it as a lake of fire or a lake of burning sulfur. The lake of fire will contain several groups:
the evil creature called the beast and his false prophet (who deceives people), whom Jesus (the Lamb) will defeat;
Satan after his final rebellion;
the powers of Death and the place of the dead (Hades); and
all people whose names are not written in God's "Book of Life."
This place is known as the second death because it completely separates people from God after the resurrection and final judgment.
Jesus likely refers to this same place using different names in his teachings. He calls it Gehenna (a valley where garbage was burned; Matthew 10:28; Mark 9:43; Luke 12:5), the “outer darkness” (Matthew 8:12; 22:13; 25:30), and the eternal fire prepared for the devil and his angels (Matthew 25:41; compare Isaiah 66:24). This description comes from two sources: the fires that burned in the valley of Hinnom near Jerusalem, and the stream of fire flowing from God's throne (Isaiah 30:33; Daniel 7:10; compare Is 34:9–10).
Both Jewish and Christian writers wrote about this place in their ancient texts (Assumption of Moses 10:10; 2 Esdras 7:36). By all these different names and descriptions, they describe the same thing: a place where those who reject God will be separated from him and suffer forever.