I don't believe in (a) God, for "religion", to me, is the coping system people found solace in during way, way shittier times.
I think that religion has been popular in foregone times, because it promised a wonderful existence in the afterlife, if you behaved well in your life(in accordance to the respective religion's ruleset).
Life sucked back then, and "religion" offered a way out.
Don't get me wrong, I'd love to think that there is an inherent reason behind all this, some kind of trial: the good are rewarded, the bad are punished.
Maybe there is, maybe there isn't, whatever it may be, I think it'd be beyond our comprehension anyway.