In the context of a letter to a brother asking for Fuller’s thoughts on preaching, Fuller discourses on the importance of preaching.
This is taken then from “Thoughts on Preaching, in Letters to a Young Minister.” Specifically from Letter 1, “Expounding the Scriptures” (The Complete Works of Andrew Fuller, I:712).
“The work in which you are engaged is of great importance. To declare the whole counsel of God in such a way as to save yourselves and them that hear you–or, if they are not saved, to be pure from their blood–is no small matter. The character of the preaching in an age contributes, more than most other things, to give a character to the Christians of that age. A great and solemn trust, therefore, is reposed in us, of which we must shortly give an account.”