This morning, I opened up Iain Murray's Lloyd-Jones: Messenger of Grace (BOT, 2008) and found a section in chapter two, "Preaching and the Holy Spirit," where Murray draws a comparison between Whitefield and Lloyd-Jones in order to illustrate the necessity of power in preaching. This is penetrating:
There is an obvious reason why preaching too often lacks the ability to hold the interest of those who listen. It is because the word spoken has no more than a fleeting access to the hearer's mind. A statement is briefly heard only to be crowded out by the individual's own thoughts, which he may well find more interesting and pleasant. Thus the twenty or forty minutes of a sermon may pass, with a person in the pose of a listener, yet actually paying attention to very little. In contrast, powerful preaching takes hold of the whole person. It gets within a man. It first arrests the mind and then speaks to the heart, the conscience, and the will. Where this element is present inattention becomes a near impossibility. Skilful oratory and carefully crafted speech can go some way to hold the hearers but it does not command attention in this manner. Powerful preaching penetrates more than the surface of the mind; it does more than merely present teaching; it is capable of causing a moral and emotional earthquake - 'not simply with words, but also with power, withthe Holy Spirit, and with deep conviction' (1 Thess. 1:4).
An eighteenth-century church-goer who was also a shipbuilder confessed that he had often built a ship from stem to stern during a sermon, but when he heard George Whitefield he found himself unable to lay a single plank. The reason for this was noted by another of the evangelist's hearers: 'Whitefield preached like a lion, he spoke as one conscious of his high credentials, with authority and power.' So it was with Lloyd-Jones. His message often carried the conviction that it was more important than any other possible consideration. (pp. 34-35, emphasis mine)