Several commenters on recent posts have brought this topic up, so I though I’d address it. What you’re going to get here is the short and dirty version, and it’s also not completely comprehensive. You have to remember that theologians have spend almost two thousand years arguing about this and that Christianity is currently so splintered that there is almost nothing all Christians agree on.
Catholics say yes
To be saved, one must be in “a state of grace.” God gives his followers grace through the sacraments, and you attain additional grace through good works, prayer, fasting, etc. If you are living in “a state of grace,” you have nothing to worry about. But just as you can have grace and gain more of it, you can also lose it.
Catholics divide the sins you can commit into two: venal sins and mortal sins. Venial sins are the little every day sins that you commit all the time almost without thinking about it. Losing your temper and yelling at your children or spouse would be a venial sin. Mortal sins involve an intentional rejection of God and his laws. Committing murder or having premarital sex would be mortal sins.
A venial sin does not deprive one of salvation, though it does lower one’s resistance to evil. A mortal sin, in contrast, shatters one’s sanctifying grace entirely and causes a loss of salvation. Imagine that salvation is like a pane of glass, and as long as you can see through it you are in a state of grace. Venial sins are smudges on that glass and mortal sins are a complete blackening of the glass. Both venial and mortal sins can be wiped away by going to confession and participating in the sacraments, but only mortal sins cause one to lose one’s “state of grace” and therefore one’s salvation.
For Catholics, then, you can lose your salvation but you can also easily regain it by going to confession and restoring your “state of grace.” If you commit a mortal sin and then die before repenting of it and going to confession (intention to go to confession counts as well), you die outside of a “state of grace” and are damned. If you commit venial sins and then die, you are still in a “state of grace” and thus avoid damnation.
Protestants say yes and no
Protestant opinion is divided on whether you can lose your salvation. Some argue that just as you can accept God you can also reject him and thus cease to be saved, but others argue that once someone is saved God will not allow that person to ever lose their salvation. There is actually a surprising amount of arguing on this point, and both sides have Bible verses to back up their views.
In practice, though, the differences become muted. Both sides agree that a saved person will follow the Bible and live a godly Christian life (which is naturally defined differently by different Christian sects).
Protestants (with the possible exception of some high church Protestants) do not believe in mortal and venial sins. Officially, they make no distinction. In practice, however, there is a sort of distinction. If a Christian individual lashes out in anger or temporarily falls prey to pornography, it’s generally seen as a sort of falling away from closeness with God that can be patched up. If a Christian individual rejects God or commits some sort of heinous sin like first degree murder or child molestation, that person’s salvation is questioned.
If a supposedly saved person rejects God or commits first degree murder, both sides of the debate will generally argue that that person is not saved (there may be exceptions, I’m generalizing here). They get there by different means, however: those who believe you can lose your salvation will say that that person lost his salvation by rejecting God, and those who believe you can’t lose your salvation will say that that person was never saved to begin with.
The whole “was never saved to begin with” thing is predicated on the fact that if someone is truly saved, if someone truly has that connection with the God of the universe, there is no way that person could ever fall away. It’s completely inconceivable. For that person to have an intimate relationship with God and then turn their back on him is impossible. Therefore, that person must never have been saved to begin with.
In practice, then, even those Christians who believe you can’t lose your salvation do not therefore believe you can go out and rape and murder and rob and still be saved, because they believe no truly saved Christian would go out and rape and murder and steal. In other words, being saved does not in practice act as an excuse to go commit crime. If you did use your “freedom in Christ” to go commit a crime, it would indicate that you hadn’t really been saved to begin with.
While Christians take different perspectives to whether or not people can be saved and then lose their salvation, they generally agree that there is a line that cannot be crossed. If someone crosses that line, Catholics will say he has committed a “mortal sin” and shattered his “state of grace,” some Protestants will say he has “lost his salvation,” and other Protestants will say he was “never saved to begin with.” Because of this, I’ve never heard of salvation being used as an excuse to go out and live a life of sin.
And now I’d like to open it up to my readers. How does the church you grew up in (or are currently a member of) approach this issue? And if you have never belonged to a church, what experiences have you had with Christians that relate to this issue?