"Whenever [Christians] have begun to think of worship chiefly as entertainment, or that what is accomplished in worship is essentially an emotional response that can be worked up by the singing of certain hymns or choruses, or that worship should consist of a series of testimonies of how people were lost in sin (with a great deal of emphasis on the sin) and were then brought to Christ - when they have substituted these other elements for careful Bible exposition in sermons, the church has always been weakened and sometimes has even died.
This is because the power of God is not in our emotions or experience but in the Word of God. His Word is what God has chosen to bless, and that is why in properly conducted Christian services we emphasize it. It is not the eloquence of the preacher or even his authority that blesses, but the Word of God."
-James Montgomery Boice