Bishop Ryle points out that Jesus, through the Holy Spirit and the ministry of the faithful church, would “raise up a standard of morality and purity and knowledge of which formerly men had no conception.” (Ryle, ibid. p. 159)
This was seen in the days immediately following the birth of the early church. The church had a tremendous impact on society.
About 375 years later, on August 24th 410 AD, the city of Rome fell to the Visigoths. Various reasons were given for this. St. Augustine, who lived at the time, believed that the immorality of the people brought the downfall of the city of Rome: “To Augustine’s way of thinking, the fall of Rome was less important than it seemed to most of his contemporaries. What was really going on was a far deeper warfare--the war between God’s kingdom and man’s; if God’s kingdom was not clearly distinguishable in this world, it is because not everyone who says they are a Christian really is. To the heathen who blamed Christianity for the downfall of the Roman Empire, Augustine showed that pagan practices actually were at fault for the weakness of the empire.
In book Two, Chapter four, (of the City of God) Augustine asked, ‘...Why were the (pagan) gods so negligent as to allow the morals of their worshippers to sink to so low a depth?...why did not those gods...lay down moral precepts that would help their devotees to lead a decent life?’
In chapter twenty-one of the same book he notes: ‘However great and good your natural gifts may be, it takes true piety to make them pure and perfect; with impurity they merely end in loss and pain.’”
http://chi.gospelcom.net/DAILYF/2002/08/daily-08-24-2002.shtml
The spiritual and moral power of the church has had great effect down through history until the Great Awakening which led to the vast missionary outreach of the church up until our own time.
But it all began with Jesus Christ and the birth of His church on the Day of Pentecost.