you can gOoGle it but
pascal was a christian mathematician
he worked a lot with statistics and probability
he said in any wager you have to do a calculation comparing what it is gonna cost with what you might win
eg
lets say you have a 6 sided dice
you bet $1
if you throw a 6 you win $2
calculation $1 : 1/6*$2 -> $1 : $0.33 -> BAD BET
now
if you throw a 6 you win $10
calculation $1 : 1/6*$10 -> $1 : $1.67 -> GOOD BET
now
live for God(and you are wrong about God) -> you die and lose nothing - NO LOSS
OR
live for Self(and you are wrong about God) -> you die and lose nothing - NO LOSS
vs
live for God(and you are RIGHT about God) -> you die and go to heaven
OR
live for Self(and you are RIGHT about God) -> you die and go to hell
SO WHY TAKE THE RISK WHEN YOU HAVE EVERYTHING TO WIN AND EVERYTHING TO LOSE