The best explanation that I can give about Hell is based on the Catholic understanding of it.
In Sacred Scripture, Hell is described as a place where people will “weep and gnash their teeth” (Mt 13:42), and is also called “the furnace of fire†(Mt 13:41-42). It is also written, “And the smoke of their torment goes up for ever and ever; and they have no rest, day or night, these worshipers of the beast and its image, and whoever receives the mark of its name" (Rev 14:11). God created Hell for the angels who rebelled against Him (2 Pet 2:4), as well as for those people who choose not to love Him or repent of their sins in this life.
God does not send to people to Hell – for He desires all to be saved (2 Pet 3:9) – but rather, people turn away from Him and remain in this state until their deaths, and so send themselves to Hell, as they have preferred creatures or mere things over and above God. In turn, God respects their free will. In Hell, people suffer from separation from God as well as from all good, and will be remorseful, although only because of the pain they are undergoing, and not for love of God. Moreover, people in Hell will have incorruptible bodies and they will feel physical pain for eternity.
Murex wrote,
“If hell does exist, I’m sure 99% of humans would be sent there. I mean, who has really followed all 10 commandments? Nobody is that pious.â€
You are right in estimating that a lot of people will go there. Even Christ said, “Enter by the narrow gate; for the gate is wide and the way is easy, that leads to destruction, and those who enter by it are many. For the gate is narrow and the way is hard, that leads to life, and those who find it are few†(Matthew 7:13-14).
Mental_Edge wrote,
“Imagine the conversation at the pearly gates. ‘Oh, I see you’ve been 51% good and 49% evil. Well, come right in. No, no, don’t worry about your 49% of wrongdoing, just go down the hall and get your wings and harp." And just imagine the reverse conversation.’â€
You’re not the first person I’ve heard of who has had this concept of how people are granted eternal life. In truth, in order to go to Heaven, a person must die in a state of grace. This assumes that he is a Christian believes in the faith. On the other hand, Catholics believe that non-Christians have the opportunity of going to Heaven, but each person’s destiny is between him and God, and this point is for another discussion altogether. As for believing Christians, someone enters the state of grace through first being baptized, where original sin is removed from the soul. People in the state of God’s grace and friendship can increase in grace by doing His will. When a person falls into the state of grave sin, he has completely turned himself away from God, and no longer abides in grace. Of course, not all hope is lost, as a person can, during his life, turn back towards God through contrition and repentance.
“Sin is an utterance, a deed, or a desire contrary to the eternal law†(St. Augustine, Faust 22:PL 42, 418); it is also an action that is contrary to reason. Mortal sins are done deliberately and with full knowledge, involve grave matter (e.g. murder), and cause a person to lose his eternal salvation. Venial sins, on the other hand, are not committed with full knowledge or with deliberate consent, and quite often do not involve grave matter (one example is idle chatter). Venial sins do not destroy a person’s friendship with God, or his eternal salvation.
It is hard to have a discussion about Hell without also going into other aspects of the Christian faith. Hell must be taken into context and should be understood in its relation with justification, the sacraments (especially baptism and penance), the atonement (Christ’s saving death), as well as predestination (who goes to Heaven?) and free will (not all Christians seem to believe in this concept).