Nation-State Religious Monarchy
In an ideal religious society, there is only one religion, the religion is the government, and the leader of the church is a legitimate prophet, seer, and revelator sustained unanimously by the population who also serves as the monarch.
For the purposes of this question, we're going to assume that this religion is indisputably, and undeniably true, as well as uncorrupt, moral and just, and that all the leadership positions in this church are unpaid and carry with them no secular status. The leaders are called to serve in their capacities (even if they feel they aren't up to the task) work harder and provide more service for the people than anyone else, they have a genuine love for their fellow citizens, and serve them in their capacity within the church out of love and devotion in addition to supporting themselves and their families secularly. Leadership positions are also regularly rotated, except for the leader and his councillors, who serve for the remainder of their lives.
To eliminate all corruption, there is no monetary system, everything goes to the church (all crops and resources) and it is the church that fairly distributes these resources to the populace.
This is a society where knowledge and understanding, and the pursuit of happiness are valued more than anything else, and everyone has a desire to improve their self worth and strive for perfection in righteousness, as well as uplift everyone they know. It is a humble, selfless, classless society, where no one is the underdog, everyone is treated as an equal, and all the dirty jobs are preformed by volunteers (the leaders volunteer more than anyone else). Sin and hypocrisy are abhorred above all else, but crime is dealt with lovingly through counseling, therapy and public service.
In order for this system to work, the church must be true and kept pure. As soon as the doctrines of men are mingled in, or corrupt men try to usurp unrighteous dominion in their leadership capacities, or dissenters try to rise against the system they must be struck down swiftly and effectively (publicly chastised, and excommunicated if necessary). Heresy is a serious crime, but is dealt with by educating the masses and calling the heretic to repentance.