I've been asked many times before, "But what if you're wrong?" I admit, if I'm wrong, and there is a god, and he is the God of the Bible, then that would really suck.
However. The chances of that are so incredibly slim, I'd be just as safe putting my faith in Ra the sun god or Aslan the lion or the angel Moroni.
Even so, to point a fine theological point on it, if the Bible is true, then the essence of this question isn't about Pascal's Wager (if you're wrong, you lose nothing; if you're right, you gain everything) but the nature of faith. In my book, I wrote a chapter addressing this very topic. Bolding is to emphasize the point here.
Pascal’s Wager Part 2:
Esau I Have Hated
My fear of hell was diminishing. It had mostly disappeared, except that every now and then, fear still momentarily struck my heart. I am literally playing with fire, I’d think. I’d get a sense that I better repent quickly just in case it all turned out to be true after all.
What I will lose if I wager wrongly! There is an eternity of suffering waiting for me should I wager against God and be wrong. What do I lose by following God and there is no God? Very little. What do I lose by not following God should there be a God? Everything. On these little occasions, I panicked about how I had played my cards, as the fear of hell crept back up on me.
Pascal’s Wager almost makes some sense, except the wager overlooks two important issues. First, it assumes that the only God worth wagering on is the Christian God, ignoring the possibility that a different religion might be the right one. Still, that issue aside, the second thing it overlooks is that without faith it is impossible to please God (Hebrews 11:6). Yet faith is a gift from God, it is not of ourselves (Ephesians 2:8). Therefore, I cannot please God without faith if he does not choose to give it to me. I could wager that God was real and keep following him as I had been doing for the past three years, but I would not be saved, for anyone who comes to him must believe that he exists (Hebrews 11:6). Pascal’s Wager is useless without faith.
Anyone who believes seriously that the Bible is God's inerrant word would have to agree that "believing" in God solely on the off-chance that he is real is not true faith at all. They would also have to agree that faith cannot be faked.
But they would also have to acknowledge that faith is a gift from God - it does not come from within ourselves. To be saved one must have genuine faith, and to have genuine faith, it must be given to one by God himself. Ergo, if God does not give you faith, you cannot be saved, end of story.
Try to insert "free will" into that wherever you like, but it really can't alter the Biblical "facts". One could try to believe on one's own, but unless God grants you faith, you're up a creek without a paddle, as they say.
"You could at least try, though. God would answer a sincere request for faith." I've heard that too. I believed that once. I hoped for that outcome for three years. Oddly enough, once the innate belief in God started to diminish, God mysteriously stopped answering my sincere request for faith.
So, to conclude my thoughts on the fatal flaws Pascal's Wager, I'll give you the rest of that chapter above.
Sadly, it was fear, not love, that sporadically warned me to reconsider God. God’s love had been gone from my life for a long time. Abandonment and silence echoed in the cavern where love once dwelled. But fear could still make me draw in a sharp breath, as it sliced through my heart like a paper cut. When I paid this fear some attention, it gathered like a thundercloud inside my head and struck my conscience with forks of lightning. I asked myself, Do you really want to bet your life on this and end up languishing in excruciating damnation for your sinful pride, your worldly “wisdom”, your pitiful human understanding, for all eternity?
Fear is a powerful tool. Yet if God’s plan for restoring my faith was fear-mongering, I was even less inclined to believe he was the God of Love I once knew – or thought – him to be. If it were the love of God striking my heart, drawing me to him, there would be something in it worth carefully considering. However, the fact that only the fear remained seemed psychologically obvious. It was neither God himself, nor his Holy Spirit, calling me back, but thirty years of theological manipulation. Hell is the scariest and most effective tool for keeping the righteous in check. Heaven’s promise pales in its alluring.
The revoked love of God in my life and the dubious possibility of heaven were not enough to draw me back to faith. The fear of hell and the almost certainty of God’s wrath, however, left me quaking. With the cards of my still unfinished life lying on the table, I could still change how I placed my bets. Yet if the God of the Bible is the one true God, my bets don’t matter in the slightest. God chooses whom he loves and whom he hates. He chose Jacob but hated Esau (Malachi 1:2-3).The cards on the table were never mine to choose from.
And we call this agape.