True virtue never appears so lovely, as when it is most oppressed; and the divine excellency of real Christianity, is never exhibited with such advantage, as when under the greatest trials: then it is that true faith appears much more precious than gold! (ref to 1 Peter 1:8)
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.
And the impressing divine things on the hearts and affections of men, is evidently one great and main end for which God has ordained that his word delivered in the holy Scriptures, should be opened, applied, and set home upon men, in preaching. And therefore it does not answer the aim which God had in this institution, merely for men to have good commentaries and expositions on the Scripture, and other good books of divinity; because, although these may tend as well as preaching to give men a good doctrinal or speculative understanding of the things of the word of God, yet they have not an equal tendency to impress them on men's hearts and affections.
Jonathan Edwards, Religious Affections