Human nature is both political and religious. Like politics, religion has numerous forms that always coexist. Modernity is regarded by many as the disappearance of religion from public sphere, but today it is obvious that faith is a part of public reason. The relationship between religion and state is uniform in the democratic spaces. State must assure liberty and safety to its citizens. Religion is not any more a structuring element, but a source of motivation in public sphere. Religious values are criteria for political choice. In European Union the Christian traditions must translate their values in a secular language, which is possible through institutional activities or personal statements. After the Second World War, in Europe, Giuseppe Lazzati was an important actor of public reason, developing significant values within his activity as a Christian and a political man. He loved God and the city. He has projected a paradigm of building la città dell’uomo (the citadel of man) in connection with human dignity of the Bible (an embodiment of faith and politics). It stands for that the Christian faith can offer one of the best patterns in the construction of the common good, even the community is secular and in a context of pluralism.