C. H. Spurgeon, perhaps the greatest preacher of the late-nineteenth century, who spoke to more than ten million people and led the largest independent church in the world at that time, attributed the fruitfulness of his entire ministry to what he called his ‘Boiler Rooms’. These were prayer rooms—often located in the basement of the building in which Spurgeon was speaking—where people would pray as he preached. Like Moses interceding with his hands held aloft by Aaron and Hur, while Joshua overcame the Amalekite armies in the valley below, Spurgeon’s prayer warriors won countless spiritual battles in those boiler rooms while the great preacher fought the earthly battle for souls from the pulpit above.