Christians LOVE to use the argument ;"what if you're wrong. If you're wrong you lose everything, but if I'm wrong i lose nothing." This is called PASCALS WAGER, and it is a silly little argument. To an inexperienced atheist this could become a stumbling block so let me advise you how to counteract this fatuous argument.
Firstly you can jab at them and say, "you're being a coward." And besides, wouldn't god sense your insecurity and know you're just trying to get out of hell? after all, he is all-knowing. While they try to counter this, kindly explain to them that this argument is silly because they DO lose something. If they are a christian and they are wrong, they will end up in muslim hell and vice versa. So pascal wager has many flaws, these are just two arguments you can use to blow a hole in their belief.