God loves mankind. So, He gave them laws that they must abide by. Breaking of God's laws results in death, destruction and doom in the eternal lake of fire. The punishment is self-inflicted.

The everlasting fire was prepared by God for the devil and his angels. – Matt 25:41, not for mankind. God loved man so much that He wanted them to live a peaceful and joyful life in a community. So, He gave them laws and commandments, which when kept, will create a conducive environment for them to live in harmony with God, as well as with fellow beings.

However, He also warned them that when these commandments are broken, the unbelief on His word and the disobedience that will follow will lead to conflict, acrimony, bitterness, war, pain and death – not just physical but an eternal separation from God – hell and everlasting fire.

It is so sad that man wants to break free from God and His laws. (also the physical laws He has set in place, like the law of gravity, which when attempted to be broken will lead to adverse results). Man refuses to comply with God’s laws and so, brings pain and death to himself and his fellow men.

This self-inflicted curse and death that follows is not what God wants for His Creation. That is why God, in His love, came among mankind again, to give him a second chance. He came down in His Son, the Lord Jesus Christ, bore the pain and curse that man had caused for himself. As man, He took the ultimate punishment – death (physical as well as the momentary separation from God) upon Himself so that all who believe in the substitutionary and atoning death of Jesus would be delivered from death and everlasting fire. He still desires all men to be saved from this ultimate punishment. God, our Saviour desires all people to be saved and to come to the knowledge of the truth. – 1Tim 2:4 (ESV 2011).

All who refuse to accept God’s way of salvation in His Son, the Lord Jesus Christ, would be judged by Him and would be sent to this everlasting fire because as much as God is love, He is holy and can’t allow sin enter heaven; He is righteous and would not tolerate inequity going unpunished.

Again, if there is no eternal punishment, then, God would not be just to all who live a God-enabled righteous life on this earth.

If there is no everlasting fire,

the terrorist that commits mass murder,
the cold-blooded murderer that kills even one’s own parents and children,
the rapist that commits heinous crime against women and children,
the adulterer and the whoremonger that causes a life-long heart-break to the spouse and destroys oneself and the family,
the sexually immoral who wants to feed his physical appetite at the cost of the other party in the crime,
the homo-sexual who is driven by an unholy passion for the unnatural, the unclean that defiles oneself with pornography, filthy conversation and compromised lifestyle,
the hater of mankind that refuses to love with a natural love,
the drunkard that destroys one’s body that is supposed to the temple of God and destroys the family,
the unbeliever who refused to accept the way of God for Salvation but trusts on his own good works,
the idolater who is ready to sacrifice even his loved ones to the idol in order to attain to his egoistic ends,
the thief that covets and appropriates the wealth and property of his fellow-men,
the corrupt politician who gulps down lives of innocent people through his unlawful dealings,
the proud who intends to subdue his neighbour in every way,
the liar who makes a lie to compromise the truth, unmindful of the adverse consequences that he might cause to people around him,
the lover of a lie who follows the liar in search of selfish gains,
the dogs that returns to their filth, are impudent and voracious,
the sorcerer and witch who finds pleasure in inflicting pain to the victim,
the fearful who refuse to rise for truth and justice (or to be called a believer, or be let down by friends and relatives for the testimony for the Lord),
the unbelieving who willingly commits serious crimes in temerity ignoring the punishment by law,
the abominable who ventures into antisocial behaviour obnoxious to the person next to him

– all of these would have the same destiny as the rest of those who have lived a godly life refraining from, abhorring and hating this above mentioned sinful lifestyle. Injustice!