"Moreover |King Ahaz| burnt incense in the valley of the son of Hinnom, and burnt his children in the fire, after the abominations of the heathen whom the Lord had cast out before the children of Israel." (2 Chronicles 28:3)
This horrible pagan ritual of child sacrifice finally ceased when good King Josiah "defiled" this Valley of Hinnom "that no man might make his son or daughter to pass through the fire to Molech" (2 Kings 23:10). The image of Molech, with its outstretched arms forming a ring of fire through which the children were made to pass, was broken to pieces and the valley itself became the dumping ground for all the garbage of Jerusalem, which was kept burning continually in the narrow deep valley so that it had the appearance of a veritable "lake of fire." As a result the valley's name of Hinnom (Greek, gehenna) came to be regarded as the name of "hell"--the place of everlasting fire where lost souls go after death.
The concept of hell and its eternal fires is a very unpopular subject in the modern world, ridiculed by skeptics and largely ignored even by evangelicals. Nevertheless, Christ Himself referred to it many times. For example: "If thy hand offend thee, cut it off: it is better for thee to enter into life maimed, than having two hands to go into hell, into the fire that never shall be quenched" (Mark 9:43). To the unsaved, He will say, "Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels" (Matthew 25:41). The term "lake of fire" is used five times in Revelation to identify the eternal prison of the devil and "whosoever was not found written in the book of life" (Revelation 20:15).
The location of the lake of fire cannot now be known; it may even be a star. In any case, it is very real, according to the Lord Jesus, who has "delivered us from the wrath to come" (1 Thessalonians 1:10). HMM