Originally posted by Atma Weapon
Final Fantasy X could present a negative or positive opinion on religion. The peoples prayers were useless and actually served to feed the demon which they prayed against. This (IMHO) is symbolic of people praying to god only to be killed by natural disasters which they beleive he caused. This theory assumes that Sin is cast in the role of god, which makes perfect logical sense considering that he is believed to be good and is worshiped by the majority of people.
However one could also assume that Sin is symbolic of satan and the worshipers of Yevon are devil worshipers who are destined to be destroyed by the one they worship. In this way FFX could be interpreted as a warning to satan worshipers. Of course one must always accept the third possiblity of this whole discussion being useless and there being no meaning or a completely different meaning behind FFX's story.
It should be known that I am an aetheist with a strong working knowledge and respect of Christianity. My opinions are in no way certain and do not take precedence of the opinions of others, but I do have an informed yet impartial view of the subject. I hope this helps if I'm not to late and you can quote me if you think i said anything quoteable.