According to Oliver O’Donovan, Book 19 of City of God “is, at the very least, an essay to demonstrate that moral philosophy must be social philosophy.” The highest good for Augustine is the peace of the city of the blessed, and this is an inherently social reality. Since virtuous action is guided by ends, and this is the supreme end of the city, the moral life is oriented to a vision of uninterrupted social peace, the eternal tranquillitas ordinis .