What is Pascal’s wager?

It refers to the argument put forward by famous French mathematician Blaise Pascal to help a person arrive at a decision on the existence of God. You’d better believe in God, Pascal argued, because if you are right, you stand to gain eternal bliss and if you are wrong, it won’t make any difference, anyway. But if you don’t believe in God, and turn out to be wrong, you are eternally damned, whereas if you are right, it makes no difference.