WIR -- Religious Affections, Jonathan Edwards

It doesn't get much more intimidating, nor more rewarding, than JE's Religious Affections. Here's a great quote (if you can follow it) on the need for existential preaching. This comes from the first chapter.

I am bold to assert, that there never was any considerable change wrought in the mind or conversation of any person, by anything of a religious nature, that ever he read, heard or saw, that had not his affections moved. Never was a natural man engaged earnestly to seek his salvation; never were any such brought to cry after wisdom, and lift up their voice for understanding, and to wrestle with God in prayer for mercy; and never was one humbled, and brought to the foot of God, from anything that ever he heard or imagined of his own unworthiness and deserving of God's displeasure; nor was ever one induced to fly for refuge unto Christ, while his heart remained unaffected. Nor was there ever a saint awakened out of a cold, lifeless flame, or recovered from a declining state in religion, and brought back from a lamentable departure from God, without having his heart affected. And in a word, there never was anything considerable brought to pass in the heart or life of any man living, by the things ofreligion, that had not his heart deeply affected by those things.