Some more quotes from "Christian Leaders of the 18th Century" by J.C.Ryle.
[Whitefield] was among the first to show the right way to meet the attacks of infidels and sceptics on Christianity. He saw clearly that the most powerful weapon against such men is not cold, metaphysical reasoning and dry critical disquisition, but preaching the whole gospel - living the whole gospel - and spreading the whole gospel... Infidels are seldom shaken by mere abstract reasoning. The surest arguments against them are gospel truth and gospel life.
"His fundamental point was to give God all the glory of whatever is good in man. In the business of salvation he set Christ as high and man as low as possible."
John Wesley, speaking about George Whitefield
The tools that the great Architect intends to use much, are often kept long in the fire, to temper them and fit them for work.