If a person believes in an authoritative god who will either reward them with a blissful eternal afterlife or torture them for all eternity based on the decisions they make here on earth, then we can never truly trust their motives to be genuine can we? They’ll feed a homeless person or donate to charity all because they think it will raise their chances to get into Heaven and avoid hell, not because they wanted to do something good for the sake of it. They’ll also execute a gay person, hang a suspected witch, or vote against equal rights for the same reasons