Hell

Defined as the "place and state of eternal punishment which consists, primarily, in the deprivation of the enjoyment and sight of God face to face (pain of loss) and, secondarily, the infliction of positive punishment by an external objective agent, called fire, which is a physical reality though unlike earthly fire (pain of sense). This punishment is not equal for all, but corresponds to the sinner's aversion from God and conversion to creatures. Only those are punished in Hell who depart this life with personal, grave, deliberate and unrepented sin....It is of faith that their punishment will never end." (Definition from A Catholic Dictionary, 1951)
 

References in Scripture:

• "As Sodom and Gomorrha, and the neighboring cities, in like manner, having given themselves to fornication, and going after other flesh, were made an example, suffering the punishment of eternal fire." St. Jude 1:7
• "And if thy hand scandalize thee, cut it off: it is better for thee to enter into life, maimed, than having two hands to go into hell, into unquenchable fire: Where there worm dieth not, and the fire is not extinguished. And if thy foot scandalize thee, cut it off. It is better for thee to enter lame into life everlasting, than having two feet, to be cast into the hell of unquenchable fire: Where their worm dieth not, and the fire is not extinguished. And if thy eye scandalize thee, pluck it out. It is better for thee with one eye to enter into the kingdom of God, than having two eyes to be cast into the hell of fire: Where the worm dieth not, and the fire is not extinguished. Mark 9:42-47
• "And it came to pass, that the beggar died, and was carried by the angels into Abraham's bosom. And the rich man also died: and he was buried in hell. And lifting up his eyes when he was in torments, he saw Abraham afar off, and Lazarus in his bosom: And he cried, and said: Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, to cool my tongue: for I am tormented in this flame. And Abraham said to him: Son, remember that thou didst receive good things in thy lifetime, and likewise Lazareth evil things, but now he is comforted; and thou art tormented. And besides all this, between us and you, there is fixed a great chaos: so that they who would pass from hence to you, cannot, nor from thence come hither." Luke 16:22-26
• "And to you who are troubled, rest with us when the Lord Jesus shall be revealed from heaven, with the angels of his power: In a flame of fire, giving vengeance to them who know not God, and who obey not the gospel of our Lord Jesus Christ. Who shall suffer eternal punishment in destruction, from the face of the Lord, and from the glory of his power" 2 Thes 1:7-9
• "Woe be to the nation that riseth up against my people: for the Lord almighty will take revenge on them, in the day of judgment he will visit them. For he will give fire, and worms into their flesh, that they may burn, and may feel for ever." Judith 16:20-21
• "Thou shalt make them as an oven of fire, in the time of thy anger: the Lord shall trouble them in his wrath, and fire shall devour them." Psalms 20:10
• "Humble thy spirit very much: for the vengeance on the flesh of the ungodly is fire and worms." Ecclesiasticus 7:19
• "Then he shall say to them also that shall be on his left hand: Depart from me, you cursed, into everlasting fire which was prepared for the devil and his angels......And these shall go into everlasting punishment: but the just, into life everlasting." Matthew 25:41,46
• "And fear ye not them that kill the body, and are not able to kill the soul: but rather fear him that can destroy both soul and body in hell" Matthew 10:28
• "And the third angel followed them, saying with a loud voice: If any man shall adore the beast and his image, and receive his character in his forehead, or in his hand; He also shall drink of the wine of the wrath of God, which is mingled with pure wine in the cup of his wrath, and shall be tormented with fire and brimstone in the sight of the holy angels, and in the sight of the Lamb. And the smoke of their torments shall ascend up for ever and ever: neither have they rest day nor night, who have adored the beast, and his image, and whoever receiveth the character of his name." Apoc 14:9-11
• "And the beast was taken, and with him the false prophet, who wrought signs before him, wherewith he seduced them who received the character of the beast, and who adored his image. These two were cast alive into the pool of fire, burning with brimstone." Apoc 19:20
• "And there came down fire from God out of heaven, and devoured them; and the devil, who seduced them, was cast into the pool of fire and brimstone, where both the beast And the false prophet shall be tormented day and night for ever and ever." Apoc 20:9-10
• "But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, they shall have their portion in the pool burning with fire and brimstone, which is the second death." Apoc 21:8
• "The Son of man shall send his angels, and they shall gather out of his kingdom all scandals, and them that work iniquity. And shall cast them into the furnace of fire: there shall be weeping and gnashing of teeth." Matt 13:41-42
• "And I say to thee: That thou art Peter; and upon this rock I will build my church, and the gates of hell shall not prevail against it" Matthew 16:18
• "Know you not that the unjust shall not possess the kingdom of God? Do not err: neither fornicators, nor idolaters, nor adulterers, Nor the effeminate, nor liers with mankind, nor thieves, nor covetous, nor drunkards, nor railers, nor extortioners, shall possess the kingdom of God" 1 Cor 6:9-10 (infers hell)
• "Now the works of the flesh are manifest, which are fornication, uncleanness, immodesty, luxury, Idolatry, witchcrafts, enmities, contentions, emulations, wraths, quarrels, dissensions, sects, Envies, murders, drunkenness, revellings, and such like. Of the which I foretell you, as I have foretold to you, that they who do such things shall not obtain the kingdom of God." Gal 5:19-21 (infers hell)

Church Teaching:

• "Moreover we define that according to the general disposition of God, the souls of those who die in actual mortal sin go down into hell immediately (mox) after death and there suffer the pain of hell. Nevertheless, on the day of judgment all men will appear with their bodies "before the judgment seat of Christ" to give an account of their personal deeds, "so that each one may receive good or evil, according to what he has done in the body"" Encyclical on the Beatific Vision of God by Pope Benedict XII, 1336
• "They that have done good shall go into life everlasting, and they that have done evil into everlasting fire" Denzinger, "Enchiridion", 10th ed., 1908, n.40
• "the souls of those who depart in mortal sin, or only in original sin, go down immediately into hell, to be visited, however, with unequal punishments" Second Council of Lyons (Denx., n. 464) and in the Decree of Union in the Council of Florence (Denz., N. 693)
   

Summary

References to hell in both Scripture and Church teaching are very, very clear. Those who do not believe in hell, or that do not believe that even one unconfessed mortal sin can lead a soul to hell, cannot claim to be Catholic.