Simply put, I think this is one of the most bullshit statements I've ever heard. The basic idea is that you cannot ever know whether God exists or not. So, you have to choose to believe or to not believe. But, in choosing, you are really making a bet. You either bet that God is real or that God is not real. If you bet that God is real and you are right, well, you hit the jackpot. If you bet that God is real and you are wrong, you don't lose too much (I think you actually lose quite a bit). If you bet that God is not real and you are right, you don't win much (this I also disagree with). And, if you bet that God is not real and you are wrong, well, you are totally fucked for all eternity. So, according to Pascal, you have to bet that God exists because it is the better overall play.
Yes, so, I have a lot of issues with this basic idea. I get it and appreciate the attempt at reasoning out the best overall outcome, but it is still a load of crapola because it doesn't incorporate all the costs. A life of belief in God and all that it requires to hold true to those beliefs, is a life filled with time and energy and thought that could be better applied to other pursuits...much better pursuits. Belief in God takes an enormous toll, particularly on the true believers. The money and time invested in a church, the neverending bible study, the avoidance of all that seems remotely inappropriate or unacceptable. Not to mention all the terror and injustice that has been carried out by individuals who truly believed that God supported their actions.
So, we are incapable of reasoning out the existence and nature of God. Therefore, we must bet on the likelihood of God's existence in the first place. Of course, we are also making some grand assumptions about God's promises and what happens to us in eternity. I mean, the bet kind of breaks apart if we know that heaven isn't much better than living on Earth, don't we? If we know there is a heaven, then we'd know there was a God...ah, this can get very hard. Anyways, we are trying to make this simple.
If we more accurately balance the scales, I think the bet is even.
In the end, what I find so frustrating is that we all know we can't prove that God exists. So those that do believe use this ridiculously simple wager, even those that don't know about Pascal, to decide that they should believe in God. It may be the safe bet, but it is the sucker's bet too.