Sam Harris challenges the notion that religion – specifically, Christianity – provides a decent basis for morality.
It’s pretty good. One quibble would be that it could be argued that the Bible doesn’t actually support the doctrine of Hell as a place of eternal, tortuous punishment and that that doctrine is actually a post-biblical invention of the Roman Catholic Church and later adopted by most other denominations.
Some will argue that non-believers have no grounds for calling anything moral or immoral because they have no absolute moral standard. Guess what: Christians don’t have one, either, despite their claims to the contrary. The biblical God is capricious and inconsistent.
Besides, there is some pretty good evidence that human morality is intuitive (or, instinctive, if you prefer). It’s internal, not external. After all, the basic elements of human morality (compassion, empathy, a sense of fairness, etc.) are found in many non-human animals, especially in those species most closely genetically related to us.
If human morality is basically genetic and is related to moral behaviour in other species, that doesn’t disprove God, of course. Rather, it’s just one more way in which God is shown to be unnecessary as an explanation.