Both belief and disbelief, by practice, in time become natural tendencies; the person who is inclined to believe gets into a habit of believing all things and everything, and an unbeliever in time comes to disbelieve everything whether right or wrong. The optimistic temperament is the temperament of the believer, and pessimism is as a rule the nature of the unbeliever. The prophets have always promised a reward for the believer, and have threatened the unbeliever with punishment, because the chance for spiritual enlightenment is only in the life of the believer, while the unbeliever covers his soul by his own disbelief.