I believe it is a sin to want to live forever.
I believe it is a sin to have faith in anything not testable.
I believe it is a sin to apply the unrealistic claims of religion, superstition, myth, occult, mysticism or the supernatural to everyday life.
I believe it is a sin to influence children into believing in an afterlife when there is no evidence supporting that claim.
I believe it is a sin to think that the salvation of the presumed soul is needed or that it can be accomplished simply through the declaration of faith in a particular doctrine.
I believe it is a sin to claim that a god's law is man's law.
I believe it is a sin to waste the greatest gift of life - the human mind - on a life based not on reason and truth, but on lies, hearsay, anecdotes and human interpretations of ancient scripture.
Go thou and sin no more.