I just got back from a trip to Vietnam and having returned from a country where religion plays a far greater part in everyday life than it does here, it prompted me to think about what we use instead.
One of the thoughts I had about this in a business context was that leaders in a largely secular environment tend to use vision to serve a lot of the same purposes as religion does in wider society.
1) Both vision and religion unite people in a common view
2) Both encourage people to see the bigger picture
3) Both provide a source of strength and direction in the tough times
I'm sure there are more but just taking those three points provides enough of a reason why you'd want to make sure that you have a clear vision for your team or organisation that everyone is bought into.