“The main benefit obtained by preaching is by impression made upon the mind at the time, and not by an effect that arises afterwards by a remembrance of what was delivered.
And though an after-remembrance of what was heard in a sermon is oftentimes very profitable; yet, for the most part, that remembrance is from an impression the words made on the heart at the time; and the memory profits, as it renews and increases that impression.
A frequent inculcating the more important things of religion in preaching has no tendency to erase out such impressions, but to increase them, and fix them deeper and deeper in the mind.”
–Jonathan Edwards, Some Thoughts Concerning the Present Revival of Religion in New England, in Edwards, The Great Awakening, ed. C.C. Goen, Vol. 4 of Works of Jonathan Edwards (New Haven, CT: Yale University Press, 1972), 397.