Hoping for the best

There's a point of tension in Christian theology regarding the assurance of salvation. On the one hand, there are biblical promises about the certainty of salvation. On the other hand, there's the specter of apostasy–as well as the phenomenon of nominal belief, where someone might have false assurance. This creates psychological tension: should we hope for the best, fear the worst, or constantly oscillate between these two moods? 

In one sense, your attitude doesn't change the outcome. If you're heavenbound, then harboring the fear that you might be hellbound doesn't change the fact that you're heavenbound. Conversely, if you're hellbound, then false assurance doesn't change the outcome.

So, in a sense, if you're hellbound, you have nothing to lose by believing that you're heavenbound. Whether you have false assurance that you are heavenbound, or rightly suspect that you are hellbound makes no difference to the outcome. Mind you, most folks who are hellbound don't think they are hellbound. Paradoxically, anxieties about your eternal destiny are more far more likely to afflict the heavenbound. 

And in a material sense, if you're heavenbound, then you have nothing to gain by the nagging doubts about your salvation, because it doesn't change the blissful outcome. But in a psychological sense, you do have something to lose–peace of mind in this life. 

In a sense, if you're hellbound, you ultimately have nothing to gain or lose by false assurance. Yet if you're heavenbound, you have nothing to gain but something to lose by harboring anxieties about your eternal fate. It robs you of joy. So you might as well hope for the best rather than fear for the worst. 

Now, I say "in a sense" because I don't mean the outcome is fatalistically inevitable regardless of what you believe or do. The point, though, is that going to heaven doesn't depend on believing for sure that you're going to heaven. You must believe in Jesus, but you don't have to believe in yourself. You don't have to have faith in your faith. 

I'd add that even in Calvinism, to say someone is heavenbound or hellbound doesn't necessarily mean they can't change course. It doesn't necessarily mean they're on a heavenbound or hellbound path from start to finish, as if where they began predetermines where they end up. You can be lost, then God saves you. If you had continued along the original trajectory for the duration, you'd wind up in hell, but where you start doesn't predict for where you arrive. There are counterfactual trajectories. 

But the main point, making allowance for the codicils, is that you have nothing to lose by hoping for the best. If you're a Christian believer, it's pointless to fear the worst.