From Peter Brown, The Rise of Western Christendom, 2nd Edition (Oxford: Blackwell Publishing), 2003, 70-71:
What was surprising to contemporaries about the Christian Church [around the year 300 AD] was the extent to which activities, which had tended to be kept separate under the old system of religio, were fused into one. Morality, philosophy, and ritual were treated as intimately connected. All were part of “religion” in the wide sense of the term to which we have become accustomed. All were based on the Law of God. They were to be found in their true form only in the Church. In the Christian churches, philosophy was dependent upon revelation and morality was absorbed into religio. Furthermoer, commitment to truth and moral improvement were held to be binding to all believers, irrespective of their class and level of culture. Hence the remarkable combination of stern moralizing and urgent theological speculation which absorbed the energy of serious Christians, from a wide variety of social backgrounds, in the third century as in all later ages.
In much the same manner, the circulation of wealth was harnessed to a carefully thought out system which linked sin with reparation through almsgiving. All classes within the Church were involved in a dogged mobilization of wealth to build up a single religious community. This wealth was distributed along the margins of the Church in such a way as to suggest that the Christian community had the will and the financial “muscle” to take care of the lowest reaches of Roman society.
Thus, when a continuous spate of laws and personal letters in favor of Christians issued from the palace of Constantine in the decades after A.D. 312, they were received and exploited to the full by a religious group which knew how to the make the best of its good fortune. If, in the words of the English proverb, “God helps those who help themselves,” the Christian Church, as it had developed in the course of the third century, more than deserved the apparent “miracle” of Constantine’s conversion at the battle of Milvian Bridge.