The re is no such historical example when all members of the society would be believers. The strengthening of faith is a very complicated process. The number of churches doesn't correlate directly with the number of believers. It is said in the Scripture that faith is God's gift. And this gift is not given to every person.
All people have to strive to be kind.
I would like to highlight it - strive to be kind. We are in lack of kindness in our modern society. We are embittered, jealous, ready to hate each other. Try to be kind and considerate, then you'll be ready for next step - morality. The communist ideologists spoke about communist moral.