What changed about the relationship of Christians to God in this transition? Why did this occur at this time?
Late eighteenth century Virginia witnessed a shift away from the strong influeneces of Puritanism in American Protestantism and rapidly toward a greater evangelicalism in Christian practice.
What changed was that the relationship between the person and God came to be much more emotional and much less formalized. This time period was early in the Second Great Awakening. This movement emphasized a very personal relationship with God that was filled with a sense of the person's need to reform and to seek a closer relationship with God.
It is always difficult to know for certain why any religious belief comes to prominence. However, historians say that this one arose as a response to the ideas of the Enlightenment. People had been drifting farther from the idea of a personal God and more towards ideas like Deism. The Second Great Awakening is seen as a response to that movement.