Start by creating a lower class comprised of those who are mentally/spiritually weak (atheists, homosexuals/sodomites). Establish a "basic income" for these people (who are now all equal with one another) with strings attached: they have to undergo rigorous Biblical education that trains them spiritually and instills patriotism, strong feelings of national pride and kinship. Those who fail to transition into this type of society (those who rebel/reject their teachings) will be either hung or stoned to death by their peers.

This subclass will be unable to vote or own property but will have guaranteed quality of life, work and lifelong purpose handed down to them from above in accordance with the roles that they are needed to fulfill at a given time.

The upper classes will be comprised of self-actualized, Christian men who have been determined (by a battery of spiritual and psychological testing) to be fit to partake in the running of the economy (free market / capitalist), government (free and democratic), and so on. About 30 to 40% of the population will make up the higher classes (though unclean or non-Christian behavior will warrant being stripped of wealth and land and placed in the lower classes).

The constitution will be the result of ongoing intellectual discussion and debate around Biblical scripture which will serve the foundation of all society. It will be through this interpretation and discussion that the purpose of the subclass will be constantly redefined/adjusted (in times of war/expansion this underclass would fight, in times of peace they would work for greater good).

This is kind of a Spark Notes version but you get the idea.