In the first of these five discourses the Preacher sets himself to clear the ground for the fitting presentation of his great theme.  He endeavours to lay down the principles on which Theologians should proceed in such discussions, and very earnestly deprecates the habit of promiscuous argument in all sorts of places, upon all sorts of occasions, and before all sorts of hearers, of the deepest and most sacred truths and mysteries of the Faith.  They only should be allowed to engage in such conversation who are fitted for it by the practice of Christian virtue.  For others there are many other subjects upon which they can exercise their dialectical attainments, without doing or incurring any injury.