Interestingly - on what the Bible actually states though - it is pretty explicit:
The Holy Bible is quite explicit in teaching the eternity of the pains of hell.
The torments of the damned shall last forever and ever (Revelation 14:11; 19:3; 20:10). They are everlasting just as are the joys of heaven (Matthew 25:46). Of Judas Christ says: "it were better for him, if that man had not been born" (Matthew 26:24). But this would not have been true if Judas was ever to be released from hell and admitted to eternal happiness. Again, God says of the damned: "Their worm shall not die, and their fire shall not be quenched" (Isaiah 66:24; Mark 9:43, 45, 47).
The fire of hell is repeatedly called eternal and unquenchable.
The wrath of God abideth on the damned (John 3:36); they are vessels of Divine wrath (Romans 9:22); they shall not possess the Kingdom of God (1 Corinthians 6:10; Galatians 5:21), etc. The objections adduced from Scripture against this doctrine are so meaningless that they are not worth while discussing in detail. The teaching of the fathers is not less clear and decisive (cf. Patavius, "De Angelis", III, viii). We merely call to mind the testimony of the martyrs who often declared that they were glad to suffer pain of brief duration in order to escape eternal torments; e.g. "Martyrium Polycarpi", c. ii (cf. Atzberger, "Geschichte", II, 612 sqq.). It is true that Origen fell into error on this point; but precisely for this error he was condemned by the Church (Canones adv. Origenem ex Justiniani libro adv. Origen., can. ix; Hardouin, III, 279 E; Denz., n. 211). In vain attempts were made to undermine the authority of these canons (cf. Dickamp, "Die origenistischen Streitigkeiten", Münster, 1899, 137). Besides even in Origen we find the orthodox teaching on the eternity of the pains of hell; for in his words the faithful Christian was again and again victorious over the doubting philosopher. Gregory of Nyssa seems to have favoured the errors of Origen; many, however, believe that his statements can be shown to be in harmony with Catholic doctrine. But the suspicions that have been cast on some passages of Gregory of Nazianzus and Jerome are decidedly without justification (cf. Pesch, "Theologische Zeitfragen", 2nd series, 190 sqq.). The Church professes her faith in the eternity of the pains of hell in clear terms in the Athanasian Creed (Denz., nn. 40), in authentic doctrinal decisions (Denz, nn. 211, 410, 429, 807, 835, 915), and in countless passages of her liturgy; she never prays for the damned.
Hence, beyond the possibility of doubt, the Church expressly teaches the eternity of the pains of hell as a truth of faith which no one can deny or call in question without manifest heresy.
The last sentence seems to say to me (but happy to be corrected if wrong) - that to believe that hell is not eternal is a heresy according to Catholicism?
http://www.newadvent.org/cathen/07207a.htm
So, it goes to show that even explicit verses like the above can be subject to interpretation and presented as a valid 'Christian' opinion on Hell. The 'Universalists' believe that hell is not eternal - but the Catholics (if I'm reading the above correctly) will disagree with them strongly.
Now, imagine how silly a Muslim would be to sit in judgement over the various Christian interpretations and insist that their particular interpretation was correct.
Cheers,
Shafique
