Augustine taught that the whole human race was “in Adam” and shared his fall. Humanity became a “mass of corruption,” incapable of any good (saving) act. Every individual, from earliest infancy to old age, is contaminated by sin and deserves nothing but damnation. Since we are capable of doing nothing good of ourselves, all power to do good must be the free gift of God—that is, grace. Out of the mass of the fallen race, God chooses some to receive this grace, which comes to them from the work of Christ, and ordinarily through the church and especially through its sacraments.
After the fall of Jerusalem in AD 70, the center of the Christian movement moved north and eventually west. The second home of the church was Antioch of Syria. Under a succession of notable bishops, the church in this third largest city of the empire took root and exerted widespread influence throughout Syria. By the end of the fourth century, Antioch was a city of half a million people, and half of these were Christians.