Lectures on Theology, published under the superintendence of his son, with a preface and memoir by the American editor, vol. I (Philadelphia: Desilver, Thomas & Co., 1836), Lecture I, "On Theology," p. 11

Religion is a barren speculation when it is treated merely as a theory. It should uniformly be represented as a practical system; the tendency of its doctrines to promote holiness of heart and life should be pointed out,…