It's an unecesary plot device, in my opinion, is all. It always leads to more moralising and preaching. I'm not saying religion is bad but I'd have been happier if I'd seen any sign that the family were in any way religious from the get go and I can't recall seeing that.

And yes, nice to see more of David's character. Took me a while to warm to him. I'm a big Colby fan :)