I haven't read John Piper's book, Bloodlines: Race, Cross and the Christian, but after watching his testimony it is on my book list.
"There was a time when the church was very powerful -- in the time when the early Christians rejoiced at being deemed worthy to suffer for what they believed. In those days the church was not merely a thermometer that recorded the ideas and principles of popular opinion; it was a thermostat that transformed the mores of society... If today's church does not recapture the sacrificial spirit of the early church, it will lose its authenticity, forfeit the loyalty of millions, and be dismissed as an irrelevant social club with no meaning for the twentieth century."
This is a quote by Martin Luther King Jr written in 1963. I found it while reading the first few pages of John Piper's book. I think the quote is as much needed now as when it was written.