What is that movie called?

What is that movie called when it starts off in some kind of
government lab and everyone working starts to die. Some guard left his
post to try to save his family. I don't remember if everyone just
dies, or gets sick or what. All the survivors of the virus, or
whatever it was have a dream about an old woman living in the country
so they all decide to go find her. They end up creating a colony and
then they start turning on power, etc.I believe that they were all
christians and it was a very religious movie. All of the surviving
"sinners" went to Vegas and started a different colony that kind of
reflected negative ways. Then something happens where Vegas ends up
getting nuked. I remember it to be a very long (maybe 6 hour) movie,
and there to be some kind of wolf tracking a certain family. (I think
the devil) I would really appreciate if anyone has any ideas about
what movie it is, I have been looking and looking, but I cannot find
it:(. Thanks!