A Treatise on the Law and the Gospel, ch. VII, "Of the Difference between the Law and the Gospel" (Edinburgh: Ogle, Allardice and Thomson, 1819), p. 158

If an exercised and disquieted Christian, do not distinctly know the difference between the law and the gospel, he cannot attain to solid tranquillity, or established comfort of soul. He will always be in danger of build…